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Sample records for indium-111 platelet scintigraphy

  1. Detection of platelet deposition at the site of peripheral balloon angioplasty using indium-111 platelet scintigraphy

    SciTech Connect

    Pope, C.F.; Ezekowitz, M.D.; Smith, E.O.; Rapoport, S.; Glickman, M.; Sostman, H.D.; Zaret, B.L.

    1985-02-01

    Restenosis after balloon angioplasty may be mediated through platelet deposition at the site of arterial dilatation. The purpose of this study was to determine whether platelet deposition at the site of dilatation could be detected using indium-111 platelet scintigraphy. Fifteen patients, aged 60 +/- 9 years, with iliac or femoral (n . 12), renal artery (n . 2) or distal aortic (n . 1) stenoses were studied. All patients received intravenous heparin at the time of dilatation. Labeled platelets containing 471 +/- 65 muCi indium-111 were injected 0.25 to 4 hours after dilatation and 1 to 24 hours after imaging. In 11 of 12 patients with iliac and femoral dilatations, focal uptake was demonstrated at the angioplasty site. In 4 patients (2 patients with renal, 1 patient with iliofemoral, and 1 with distal aortic stenoses), uptake at the dilatation sites was not detected. This preliminary study indicates that despite intravenous heparin, platelets accumulate at sites of balloon dilatation. Platelet scintigraphy may be useful in predicting sites of future narrowing after angioplasty and may be used to test the efficacy of antiplatelet therapy in retarding restenosis.

  2. Platelet aggregability and in vivo platelet deposition in patients with ischemic cerebrovascular disease--evaluation by indium-111-platelet scintigraphy

    SciTech Connect

    Isaka, Y.; Kimura, K.; Uehara, A.; Hashikawa, K.; Mieno, M.; Matsumoto, M.; Handa, N.; Nakabayashi, S.; Imaizumi, M.; Kamada, T. )

    1989-12-15

    In ischemic cerebrovascular disease, it is not clear whether platelet function in vitro actually reflects the situation in vivo. Using indium-111 platelet scintigraphy as a method for detecting platelet activation in vivo, we tried to elucidate this problem. Twenty eight patients with chronic stage of ischemic cerebrovascular disease (CVD) and 17 control subjects were examined. Platelet scintigrams were positive in 9 of 28 patients in CVD, while all were negative in control. A comparison of the results obtained from qualitative platelet imaging and platelet aggregability was performed to evaluate whether threshold aggregation concentration (TAC) grade differed across the three groups (control, CVD patients without platelet deposition and CVD patients with platelet deposition). CVD patients with platelet deposition showed a higher TAC than those patients who did not show platelet deposition (P less than 0.05) or control subjects without platelet deposition (P less than 0.05). These results suggest that some patients in chronic stages of CVD may have active platelet deposition on carotid atheromatous lesions, and presence of platelet deposition in vivo could contribute to reduce platelet reactivity in peripheral blood.

  3. Platelet aggregability and in vivo platelet deposition in patients with ischemic cerebrovascular disease--evaluation by indium-111-platelet scintigraphy.

    PubMed

    Isaka, Y; Kimura, K; Uehara, A; Hashikawa, K; Mieno, M; Matsumoto, M; Handa, N; Nakabayashi, S; Imaizumi, M; Kamada, T

    1989-12-15

    In ischemic cerebrovascular disease, it is not clear whether platelet function in vitro actually reflects the situation in vivo. Using indium-111 platelet scintigraphy as a method for detecting platelet activation in vivo, we tried to elucidate this problem. Twenty eight patients with chronic stage of ischemic cerebrovascular disease (CVD) and 17 control subjects were examined. Platelet scintigrams were positive in 9 of 28 patients in CVD, while all were negative in control. A comparison of the results obtained from qualitative platelet imaging and platelet aggregability was performed to evaluate whether threshold aggregation concentration (TAC) grade differed across the three groups (control, CVD patients without platelet deposition and CVD patients with platelet deposition). CVD patients with platelet deposition showed a higher TAC than those patients who did not show platelet deposition (P less than 0.05) or control subjects without platelet deposition (P less than 0.05). These results suggest that some patients in chronic stages of CVD may have active platelet deposition on carotid atheromatous lesions, and presence of platelet deposition in vivo could contribute to reduce platelet reactivity in peripheral blood. PMID:2633402

  4. Comparison of indium-111 platelet scintigraphy and two-dimensional echocardiography in the diagnosis of left ventricular thrombi

    SciTech Connect

    Ezekowitz, M.D.; Wilson, D.A.; Smith, E.O.; Burow, R.D.; Harrison, L.H. Jr.; Parker, D.E.; Elkins, R.C.; Peyton, M.; Taylor, F.B.

    1982-06-24

    In a study comparing indium-111 platelet scintigraphy and two-dimensional echocardiography as methods of identifying left ventricular thrombi, the results obtained with both techniques were verified at surgery or autopsy in 53 patients-34 with left ventricular aneurysms, and 19 with mitral-valve disease. Left ventricular thrombi were found at surgery or autopsy in 14 of the patients with aneurysms and in none of those with mitral-valve disease. Thirteen of 53 echocardiograms (25%) were technically inadequate and excluded from the analysis. In the group with aneurysms, the sensitivity of scintigraphy in detecting thrombi was 71%, and that of echocardiography was 77%. The specificity of scintigraphy was 100%, and that of echocardiography was 93%. We conclude that indium-111 platelet scintigraphy and two-dimensional echocardiography have useful and complementary roles in the detection of left ventricular thrombi. Both these noninvasive techniques can be used to monitor therapy.

  5. Identification of intracardiac thrombi in stroke patients with indium-111 platelet scintigraphy

    SciTech Connect

    Kessler, C.; Henningsen, H.; Reuther, R.; Kimmig, B.; Roesch, M.

    1987-01-01

    Platelet scintigraphy (PSC) with indium-111 labelled platelets has been confirmed as an adequate method for the detection of intracardiac thrombi in patients with heart disease. We performed PSC of the heart and the neck vessels in 27 stroke patients with suspected cardiac embolism and as control on 10 patients with atherosclerotic lesions of the carotid arteries without evidence of heart disease. The carotid PSC was positive in 6 of 10 patients with carotid disease, and twice in the 27 with suspected cardiac embolism. In these 27 the PSC of the heart indicated pathological conditions 13 times. Pathological platelet accumulations could be visualized in 3 cases in the atrial space, in 9 cases in the region of the left ventricle, and once at the aortic valve. Scintigraphy was negative in all 10 patients with atherosclerosis of the neck vessels. The two-dimensional echocardiography revealed pathological findings in 8 of the 13 patients with positive heart PSC (3 with intraventricular thrombi, 3 with valvular disease, 2 with decreased ventricular contractility) and was normal in the 10 control patients. Open-heart surgery was performed in 2 patients with pathological PSC and revealed an intracardiac thrombus. Three of 4 patients with positive atrial PSC showed mitral or aortic valve disease. These results suggest that PSC can provide a valuable method for detecting cardiac thrombi in stroke patients.

  6. Early diagnosis of acute postoperative renal transplant rejection by indium-111-labeled platelet scintigraphy

    SciTech Connect

    Tisdale, P.L.; Collier, B.D.; Kauffman, H.M.; Adams, M.B.; Isitman, A.T.; Hellman, R.S.; Hoffmann, R.G.; Rao, S.A.; Joestgen, T.; Krohn, L.

    1986-08-01

    A prospective evaluation of /sup 111/In-labeled platelet scintigraphy (IPS) for the early diagnosis of acute postoperative renal transplant rejection (TR) was undertaken. The results of IPS were compared with in vitro biochemical tests, the clinical finding of graft tenderness, and combined (/sup 99m/Tc)DTPA and (/sup 131/I)orthoiodohippurate scintigraphy. With a sensitivity of 0.93 and a specificity of 0.95, IPS provided otherwise unavailable diagnostic information. Furthermore, postoperative IPS was a good predictor of long-term allograft survival.

  7. The use of indium-111 oxine platelet scintigraphy and survival studies in pediatric patients with thrombocytopenia

    SciTech Connect

    Castle, V.P.; Shulkin, B.L.; Coates, G.; Andrew, M. )

    1989-11-01

    We have utilized {sup 111}In-labeled heterologous platelets to investigate the mechanism of thrombocytopenia in ten children. From the scintigraphic findings, platelet survival times, and clinical information, thrombocytopenia was ascribed to decreased production or to increased destruction. Two patients were found to have bone marrow production defects. Two patients with hemangiomas were studied. In one, the hemangioma was shown not to be the cause of thrombocytopenia. In the second, the hemangioma was proven the source of platelet destruction, but was much more extensive than clinically evident. In both, surgical manipulation of the hemangioma was avoided. Six additional patients had thrombocytopenia due to accelerated destruction. In four, the spleen was shown responsible. In two, however, the spleen was shown not to be responsible for the low platelet counts, and splenectomy was avoided. Thus, {sup 111}In-platelet scintigraphy and survival studies are valuable in the classification and management of childhood thrombocytopenia. We believe that this study should be performed, when possible, in any child with thrombocytopenia where the mechanism is unclear or the therapeutic intervention involves splenectomy or resection of a hemangioma.

  8. Effect of aspirin and ticlopidine on platelet deposition in carotid atherosclerosis: assessment by indium-111 platelet scintigraphy

    SciTech Connect

    Isaka, Y.; Kimura, K.; Etani, H.; Uehara, A.; Uyama, O.; Yoneda, S.; Kamada, T.; Kusunoki, M.

    1986-11-01

    The antiplatelet effects of aspirin and ticlopidine were studied by a dual-tracer method, using indium-111 labeled platelets and technetium-99m human serum albumin, in a group of 12 patients with suspected ischemic cerebrovascular disease. The magnitude of platelet accumulation at the carotid bifurcation was expressed as the ratio of radioactivity of indium-111 platelets deposited on the vascular wall to those circulating in the blood-pool (PAI, platelet accumulation index), 48 hr after injection of labeled platelets. PAI values were measured before (baseline studies) and after the antithrombotic therapies (aspirin studies: 325 mg bid for 22.3 +/- 1.3 days, ticlopidine studies: 100 mg tid for 21.8 +/- 2.1 days). At the baseline, the mean PAI value at 24 carotid bifurcations in the patient group was 15.7 +/- 15.3% (mean +/- S.D.) compared to -4.3 +/- 9.1 at 24 carotid bifurcations in 12 normal subjects (p less than 0.01). We defined the upper limit for a normal PAI (%) value to be +13.9, namely the mean PAI plus 2 SD for the carotid bifurcation in normal subjects and used this value for semiquantitative analysis. At the baseline, significant elevation of PAI (more than 13.9%; positive scintigram) was observed at 12 of 24 vessels, while 12 other regions were negative (less than 13.9%). In the lesions with positive scintigraphic results at the baseline, the mean PAI (%) value from the baseline, aspirin and ticlopidine studies was 29.5 +/- 7.0, 11.2 +/- 8.5 (p less than 0.01 versus baseline) and 21.4 +/- 21.3 (not significant from baseline), respectively.

  9. Pitfalls in establishing the diagnosis of deep venous thrombophlebitis by indium-111 platelet scintigraphy

    SciTech Connect

    Seabold, J.E.; Conrad, G.R.; Kimball, D.A.; Ponto, J.A.; Bricker, J.A.

    1988-07-01

    Forty-seven /sup 111/In-platelet scintigraphs (In-PS) were analyzed retrospectively to identify sources of diagnostic error and to optimize the diagnostic criteria for active deep venous thrombophlebitis (DVT). The results of In-PS were compared with contrast venography, additional diagnostic studies, and clinical outcome. Three patterns of platelet localization emerged as the best predictors of active DVT: (a) focal or (b) linear 4-hr localization, or (c) an asymmetric blood-pool pattern on 4-hr imaging that evolved into a focal or linear pattern by 16 to 24 hr. All false-positive studies had abnormal patterns confined to the inguinal region at 24 hr. All patients with false-negative studies had received heparin between 4 and 24 hr. The potential pitfalls encountered in the evaluation of the iliac, femoral, and popliteal veins are reviewed and the importance of delayed imaging in selected cases is emphasized.

  10. Detection of accessory spleens with indium 111-labeled autologous platelets

    SciTech Connect

    Davis, H.H., II; Varki, A.; Heaton, W.A.; Siegel, B.A.

    1980-01-01

    In two patients with recurrent immune thrombocytopenia, accessory splenic tissue was demonstrated by radionuclide imaging following administration of indium 111-labeled autologous platelets. In one of these patients, no accessory splenic tissue was seen on images obtained with technetium 99m sulfur colloid. This new technique provides a simple means for demonstrating accessory spleens and simultaneously evaluating the life-span of autologous platelets.

  11. Indium-111 leukocyte scintigraphy in Wegener's granulomatosis involving the spleen

    SciTech Connect

    Morayati, S.J.; Fink-Bennett, D.

    1986-12-01

    Indium-111-labeled leukocyte scintigraphy was performed on a 44-yr-old man to exclude an occult abscess. Four- and twenty-four-hour images of the abdomen revealed splenic photopenia except for a rim of activity medially. A subsequent computed tomography (CT) study demonstrated necrosis or hemorrhage of the spleen except for a medial rim. Exploratory laparotomy demonstrated necrotizing vasculitis with granuloma formation consistent with Wegener's granulomatosis and a rim of viable splenic tissue corresponding to the radionuclide and CT studies.

  12. Detection of deep venous thrombosis by indium-111 leukocyte scintigraphy

    SciTech Connect

    D'Alonzo, W.A. Jr.; Alavi, A.

    1986-05-01

    Indium-111-labeled leukocyte ((/sup 111/In)WBC) scintigraphy has been used successfully for detection of inflammation. Occasionally, noninflammatory collections of white blood cells such as hematomas or hemorrhage have been localized. We report a case in which unsuspected femoral deep venous thrombosis was diagnosed on an (/sup 111/In)WBC leukocyte scan performed for detection of osteomyelitis. Readers are advised to avoid interpreting all vascular (/sup 111/In)WBC localization as necessarily infectious. This may be of particular significance in patients with vascular grafts.

  13. Indium-111-labeled leukocyte scintigraphy in hemodialysis access-site infection

    SciTech Connect

    Palestro, C.J.; Vega, A.; Kim, C.K.; Vallabhajosula, S.; Goldsmith, S.J. )

    1990-03-01

    Bacterial sepsis, a significant complication of chronic hemodialysis, is generally the result of infection at the vascular access site. We retrospectively reviewed the utility of indium-111-(111In) labeled autologous leukocyte scintigraphy in 26 patients (30 scans) with synthetic vascular grafts, on chronic hemodialysis, in whom hemodialysis access site infection was a diagnostic consideration. Leukocyte scintigraphy correctly identified all fifteen access-site infections; there was one false-positive study, for an overall sensitivity and specificity of 100% and 93%, respectively. Of particular significance is the fact that in nine (60%) of the fifteen access-site infections, physical examination was normal. Our data indicate that 111In-labeled leukocyte scintigraphy is a useful procedure for the diagnosis of hemodialysis access-site infection, and it is especially valuable when physical examination of the access site is normal.

  14. Indium-111-chloride and three-phase bone scintigraphy: A comparison for imaging experimental osteomyelitis

    SciTech Connect

    Hoskinson, J.J.; Daniel, G.B.; Patton, C.S. )

    1991-01-01

    To investigate the utility of indium-111-chloride ({sup 111}In-Cl) imaging in detecting osteomyelitis complicating surgical or fracture sites, the proximal tibia of 11 dogs were experimentally infected with Staphylococcus aureus after creation of a cortical defect. The contralateral limb served as a sham-operated control. Animals were serially imaged by radiography, three-phase technetium-99m-methylene diphosphonate (99mTc-MDP) scintigraphy, and {sup 111}In-Cl scintigraphy. There was a significant difference between infected (1.93) and noninfected (1.32) limb's tibia/femur count density ratios on 24-hr (p = 0.0001) and 72-hr (p = 0.0001) {sup 111}In-Cl images. A smaller difference was found for 99mTc-MDP bone-phase tibia/femur ratios (p = 0.0199). Using receiver operator characteristic analysis of tibia/femur ratios, a sensitivity of 61%, specificity of 88%, and positive (75%) and negative (79%) predictive values were determined for the 24-hr {sup 111}In-Cl images. Indium-111-chloride was superior to 99mTc-MDP in differentiating infected and noninfected operative sites.

  15. Thyrotropinoma with Graves’ disease detected by the fusion of indium-111 octreotide scintigraphy and pituitary magnetic resonance imaging

    PubMed Central

    Okuyucu, Kursat; Alagoz, Engin; Arslan, Nuri; Taslipinar, Abdullah; Deveci, Mehmet Salih; Bolu, Erol

    2016-01-01

    Thyroid-stimulating hormone-secreting pituitary adenoma (TSHoma) is a rare benign endocrinological tumor which produces TSH in the pituitary gland. Herein, we presented a female patient having TSHoma with Graves’ disease during and just after pregnancy that we found by indium-111 octreotide scintigraphy while investigating the patient for hyperthyroidism symptoms. PMID:27095865

  16. Thyrotropinoma with Graves' disease detected by the fusion of indium-111 octreotide scintigraphy and pituitary magnetic resonance imaging.

    PubMed

    Okuyucu, Kursat; Alagoz, Engin; Arslan, Nuri; Taslipinar, Abdullah; Deveci, Mehmet Salih; Bolu, Erol

    2016-01-01

    Thyroid-stimulating hormone-secreting pituitary adenoma (TSHoma) is a rare benign endocrinological tumor which produces TSH in the pituitary gland. Herein, we presented a female patient having TSHoma with Graves' disease during and just after pregnancy that we found by indium-111 octreotide scintigraphy while investigating the patient for hyperthyroidism symptoms. PMID:27095865

  17. Appearance of acute gouty arthritis on indium-111-labeled leukocyte scintigraphy

    SciTech Connect

    Palestro, C.J.; Vega, A.; Kim, C.K.; Swyer, A.J.; Goldsmith, S.J. )

    1990-05-01

    Indium-111-labeled leukocyte scintigraphy was performed on a 66-yr-old male with polyarticular acute gouty arthritis. Images revealed intense labeled leukocyte accumulation in a pattern indistinguishable from septic arthritis, in both knees and ankles, and the metatarsophalangeal joint of both great toes, all of which were involved in the acute gouty attack. Joint aspirate as well as blood cultures were reported as no growth; the patient was treated with intravenous colchicine and ACTH for 10 days with dramatic improvement noted. Labeled leukocyte imaging, repeated 12 days after the initial study, revealed near total resolution of joint abnormalities, concordant with the patient's clinical improvement. This case demonstrates that while acute gouty arthritis is a potential pitfall in labeled leukocyte imaging, in the presence of known gout, it may provide a simple, objective, noninvasive method of evaluating patient response to therapy.

  18. Indium-111 labeled platelet survival time studies in patients with prosthetic heart valves

    SciTech Connect

    Martinovitch, U.; Carrick, P.; Lieberman, L.M.

    1985-05-01

    Platelet survival time (PST) studies are useful to demonstrate whether or not patients with prosthetic heart valves have normal or shortened PST. During treatment for recurrent TIAs the PST will signal whether the patient is returning towards a normal PST. Using Indium-111 labeled platelets (ILP) the authors studied 10 patients suffering recurrent TIAs after prosthetic valve surgery to determine whether low dose aspirin increased their PST toward normal and whether the treatment had a beneficial effect on their TIA episodes. The authors conclude that low dose aspirin therapy as studied by ILP has no beneficial effect on PST or in preventing recurrent TIA. ILP is an important technique that allows the physician to identify those patients with shortened PST and to determine response to therapy.

  19. Indium-111-granulocyte scintigraphy in brain abscess diagnosis: Limitations and pitfalls

    SciTech Connect

    Schmidt, K.G.; Rasmussen, J.W.; Frederiksen, P.B.; Kock-Jensen, C.; Pedersen, N.T. )

    1990-07-01

    The scintigrams and records of 28 patients referred for indium-111-granulocyte scintigraphy (111In-GS) because of a suspected brain abscess were studied retrospectively. The final diagnosis was brain abscess in 8 patients, brain tumor in 18 patients, and infarct and hematoma in 1 patient each. Five patients not on corticosteroid treatment showed intense focal 111In accumulation in abscesses, whereas an abscess patient receiving a high steroid dose showed no uptake. Two patients studied twice showed intense uptake in abscesses when not on steroid therapy or on a low dose, whereas no uptake was seen when they received high or medium doses. Weak or moderate 111In uptake was observed in nine tumors. Microscopically assessed degree of tumor granulocyte infiltration, vessel proliferation, and hemorrhage did not correlate with the outcome of 111In GS. Our results suggest that intense focal cerebral 111In uptake favors the abscess diagnosis. Abscesses may go undetected, however, in patients on high- or medium-dose steroid therapy.

  20. Platelet kinetics with indium-111 platelets: comparison with chromium-51 platelets.

    PubMed

    Peters, A M; Lavender, J P

    1983-04-01

    The application of 111In-oxine to platelet labeling has contributed to the understanding of platelet kinetics along three lines: 1. It allows the measurement of new parameters of splenic function, such as the intrasplenic platelet transit time, which has shed new light on the physiology of splenic blood cell handling. 2. It facilitates the measurement of platelet life span in conditions, such as ITP, in which 51Cr may undergo undesirable elution from the platelet as a result of platelet-antibody interaction. 3. It allows the determination of the fate of platelets, that is, the site of platelet destruction in conditions in which reduced platelet life span is associated with abnormal platelet consumption, as a result of either premature destruction of "abnormal" platelets by the RE system, or the consumption (or destruction) of normal platelets after their interaction with an abnormal vasculature. Future research using 111In platelets may yield further valuable information on the control as well as the significance of intrasplenic platelet pooling, on the role of platelets in the development of chronic vascular lesions, and on the sites of platelet destruction in ITP. With regard to the latter, methods will have to be developed for harvesting sufficient platelets representative of the total circulating platelet population from severely thrombocytopenic patients for autologous platelet labeling. This would avoid the use of homologous platelets, which is likely to be responsible for some of the contradictory data relating to the use of radiolabeled platelet studies for the prediction of the response of patients with ITP to splenectomy. PMID:6346489

  1. Reduction of indium-111 platelet deposition on Dacron vascular grafts in humans by aspirin plus dipyridamole

    SciTech Connect

    Stratton, J.R.; Ritchie, J.L.

    1986-02-01

    Aspirin plus dipyridamole reduces platelet accumulation on short-term Dacron vascular grafts in man. To determine whether drug inhibition of platelet deposition is sustained on older grafts, we studied 18 men aged 41 to 87 years who had Dacron aortic bifurcation grafts in place a mean of 43.4 months (range 9.8 to 121.0) before and during short-term therapy with aspirin (325 mg tid) plus dipyridamole (75 mg tid). During both the baseline and drug studies, indium-111 (/sup 111/In) platelet deposition was quantitated by two techniques, standard planar imaging performed at 24, 48, and 72 hr after injection of platelets and single photon emission computed tomographic imaging performed at 24 and 72 hr after injection. All analyses were performed in a blinded fashion. On both the planar and tomographic images, platelet accumulation on the graft was quantitated by a graft/blood ratio that compared activity in the graft to simultaneously collected whole blood /sup 111/In platelet activity. Aspirin plus dipyridamole reduced the tomographic graft/blood ratio at 24 hr (20.6 +/- 3.5 vs 17.3 +/- 2.5) (+/-SEM) and at 72 hr (29.0 +/- 4.8 vs 25.0 +/- 4.1) after injection of platelets (p = .02). Dacron vascular grafts. Similarly, the planar graft/blood ratio was reduced at 24 hr (2.7 +/- 0.5 vs 2.4 +/- 0.5), 48 hr (3.7 +/- 0.9 vs 3.1 +/- 0.7), and 72 hr (4.0 +/- 0.9 vs 3.6 +/- 0.8) (p = .04). We conclude that aspirin (325 mg tid) plus dipyridamole (75 mg tid) reduces platelet accumulation on long-term Dacron vascular grafts.

  2. Uptake of indium-111-labeled platelets and indium-111 oxine by murine kidneys after total-body irradiation

    SciTech Connect

    Ebbe, S.; Taylor, S.; Maurer, H.; Kullgren, B.

    1996-08-01

    Radiation nephropathy is a well-known late manifestation of renal irradiation in human beings and experimental animals. Its pathogenesis is unclear, but vascular injury may play a role. Endothelial cells have been demonstrated to manifest a variety of abnormalities within hours of exposure to radiation. In the present experiments mice were exposed to lethal doses of whole-body radiation, and the distribution of {sup 111}In-labeled platelets was evaluated during the first week after irradiation. The purpose was to determine if early abnormalities of endothelial cells would be manifested by altered sequestration of platelets in kidneys and other organs. It was found that the indium accumulated in the kidneys of irradiated mice to a greater extent than in nonirradiated mice, but the pattern of accumulation differed from that seen after injection of radiolabeled platelets. Renal hyperemia was not demonstrable with {sup 51}Cr-labeled red cells, renal vascular permeability was not detected with {sup 125}I-labeled albumin, and the pattern of renal uptake of plasma proteins labeled albumin, and the pattern of renal uptake of plasma proteins labeled with {sup 59}Fe {sup 111}In did not coincide with that seen from {sup 111}In administered as labeled platelets or oxine. Renal uptake of {sup 111}In-oxine was not associated with alterations in urinary or fecal excretion or an increase in total-body retention of the radioisotope. The findings are consistent with the notion that renal vascular injury at the time of irradiation results in accumulation of platelets or platelet constituents during the first week after total-body irradiation of mice. 29 refs., 5 figs., 3 tabs.

  3. Failure of ticlopidine to inhibit deposition of indium-111-labeled platelets on Dacron prosthetic surfaces in humans

    SciTech Connect

    Stratton, J.R.; Ritchie, J.L.

    1984-04-01

    In a randomized double-blind trial we sought to determine whether short-term therapy with ticlopidine (250 mg bid for 14 days) inhibited platelet deposition on Dacron aortic bifurcation grafts that had been in place a year or longer. A total of 10 men, 42 to 69 years old, underwent indium-111 platelet imaging during both placebo and drug phases of the trial at 24, 48, and 72 hr after the injection of labeled platelets. Platelet accumulation was quantitated by a graft/blood ratio that compared background-corrected activity of indium-111-labeled platelets in the graft with whole-blood activity of indium-111-labeled platelets. Additionally, blinded qualitative visual analysis of the unprocessed images was used to compare graft area activity with activity in adjacent native arteries. Ticlopidine significantly prolonged the template bleeding time from 5.3 +/- 0.5 to 17.1 +/- 3.1 min (+/- SEM) (p . .003). However, by quantitative analysis there was no significant reduction in platelet deposition in the graft during ticlopidine therapy compared with placebo at 24 hr (graft/blood ratio 2.3 +/- 0.4 vs 2.6 +/- 0.3), 48 hr (3.1 +/- 0.5 vs 3.2 +/- 0.4), or 72 hr (3.9 +/- 0.7 vs 4.0 +/- 0.6) after injection of labeled platelets. By visual analysis, nine patients had positive results for abnormal platelet deposition when on placebo that were unchanged when on ticlopidine. The tenth patient had an equivocal result for abnormal platelet deposition when on placebo and a negative result for abnormal platelet deposition when on ticlopidine.(ABSTRACT TRUNCATED AT 250 WORDS)

  4. Uptake of indium-111 labelled platelets by normal, nephrotic and transplanted kidneys

    SciTech Connect

    Desir, G.; Lange, R.; Smith, E.; Bia, M.; Flye, M.; Kashgarian, M.; Canganelli, A.; Ezekowitz

    1984-01-01

    To determine the role of platelets in the genesis of renal transplant (T) rejection, the authors studied 3 groups of adult patients. Group I, n=8, had normal renal function (Cr=1 +- 0.1 mg%, Mean +- SD). Group II, n=9, had nephrotic syndrome (Cr=2.4 +- 1). Group III, n=7, consisted of 5 cadaveric (C) and 2 living related donor (LRD) T. In Group II, 1 patient had received a T 4 years prior to study. Group I and II received 448 +- 101 ..mu..Ci and Group III 236 +- 51 ..mu..Ci of Indium-111. In Groups I and II the first image was obtained 18 +- 6 hrs after injection. In Group II the first was obtained 6 +- 2 hr after injection and 1-3 times/day thereafter for a maximum of 7 days. Renal biopsies were obtained in all patients in Group III during imaging (n=5) or within 2 - 5 days of the last image. One patient was studied twice. In Group III, 5 patients received prednisone and azothiaprine and 2 prednisone and cyclosporine. Platelet uptake index (PUI) was calculated as the ratio of uptake over the T against a reference area. Rejection was diagnosed by biopsy. In groups I and II platelet uptake was seen only in the T patient. In Group III the PUI was 1.54 +- .13 in the rejecting T (n=5), 1.42 +- .2 in the non-rejecting T (n=3), 1.62 in a LRD non-rejecting T and 1.31 (n=2) in C non-rejecting T. In the four patients studied within 5 days of T the PUI was elevated at 1.47 +- .1. The authors conclude that: 1) platelets do not accumulate in normal or nephrotic native kidneys, 2) significant uptake occurs in the first week after C and LRD whether or not rejection is present, and 3) uptake in non-rejecting kidneys cannot be ascribed to perfusion induced endothelial injury since it was present in LRD transplants.

  5. Early Indium-111 antimyosin scintigraphy for assessment of regional wall motion asynergy on discharge after myocardial infarction

    SciTech Connect

    van Vlies, B.; Baas, J.; Visser, C.A.; van Royen, E.; Delemarre, B.J.; Bot, H.; Dunning, A.J. )

    1990-01-01

    To assess the relation between early Indium-111 monoclonal antimyosin antibody scintigraphy and degree of regional asynergy on discharge, 38 patients with a first acute myocardial infarct were studied (18 anterior, 20 inferoposterior infarctions). In 21 patients thrombolytic therapy was administered. On the first day of myocardial infarction, 80 MBq Indium-111 Antimyosin was injected. Planar images, anterior, lateral and left anterior oblique, were made 24 hours later. Localized myocardial uptake was present in 37/38 patients, and was evaluated for Count Density Index (count density of infarct zone/left lung count density) in the left anterior oblique images, which displayed the infarct zone well. Regional asynergy on discharge was evaluated by cross-sectional echocardiography and defined mild (hypokinesia) or severe (akinesia or dyskinesia). Count density index was significantly lower in 15 patients with mild asynergy, compared with 22 patients with severe asynergy (1.61 +/- 0.25 vs. 2.42 +/- 0.40, p less than 0.001). This difference was present in both patient groups treated with or without thrombolysis. We conclude that early count density index, reflecting the amount of local necrosis, is highly correlated to the ultimate degree of wall motion impairment.

  6. Platelet destruction in autoimmune thrombocytopenic purpura: kinetics and clearance of indium-111-labeled autologous platelets

    SciTech Connect

    Stratton, J.R.; Ballem, P.J.; Gernsheimer, T.; Cerqueira, M.; Slichter, S.J.

    1989-05-01

    Using autologous /sup 111/In-labeled platelets, platelet kinetics and the sites of platelet destruction were assessed in 16 normal subjects (13 with and three without spleens), in 17 studies of patients with primary autoimmune thrombocytopenic purpura (AITP), in six studies of patients with secondary AITP, in ten studies of patients with AITP following splenectomy, and in five thrombocytopenic patients with myelodysplastic syndromes. In normal subjects, the spleen accounted for 24 +/- 4% of platelet destruction and the liver for 15 +/- 2%. Untreated patients with primary AITP had increased splenic destruction (40 +/- 14%, p less than 0.001) but not hepatic destruction (13 +/- 5%). Compared with untreated patients, prednisone treated patients did not have significantly different spleen and liver platelet sequestration. Patients with secondary AITP had similar platelet counts, platelet survivals, and increases in splenic destruction of platelets as did patients with primary AITP. In contrast, patients with myelodysplastic syndromes had a normal pattern of platelet destruction. In AITP patients following splenectomy, the five nonresponders all had a marked increase (greater than 45%) in liver destruction compared to five responders (all less than 40%). Among all patients with primary or secondary AITP, there was an inverse relationship between the percent of platelets destroyed in the liver plus spleen and both the platelet count (r = 0.75, p less than 0.001) and the platelet survival (r = 0.86, p less than 0.001). In a stepwise multiple linear regression analysis, total liver plus spleen platelet destruction, the platelet survival and the platelet turnover were all significant independent predictors of the platelet count. Thus platelet destruction is shifted to the spleen in primary and secondary AITP. Failure of splenectomy is associated with a marked elevation in liver destruction.

  7. Indium-111 platelet imaging for detection of platelet deposition in abdominal aneurysms and prosthetic arterial grafts

    SciTech Connect

    Ritchie, J.L.; Stratton, J.R.; Thiele, B.; Haminton, G.W.; Warrick, L.N.; Huang, T.W.; Harker, L.A.

    1981-04-01

    Thirty-four platelet imaging studies were performed in 23 patients to determine whether platelet deposition could be detected in patients with vascular aneurysms (18 patients) or in patients in whom Dacron prosthetic grafts had been placed (5 patients). In patients in whom abnormal platelet deposition was detected, the effect of administration of platelet-active drugs on platelet deposition was examined. Of the 18 patients with an aneurysm, 12 had equivocally positive studies on initial imaging and 2 had equivocally positive images. Of five patients with Dacron arterial grafts in place, four had diffuse platelet deposition in the grafts; the fifth patient had a platelet deposition only in a pseudoaneurysm. Eight patients with an abdominal aneurysm and positive or equivocally positive baseline images were restudied during platelet-active drug therapy either with aspirin plus dipyridamole (seven patients) or with sulfinpyrazone (four patients). No patient studied during treatment with aspirin plus dipyridamole had detectably decreased platelet deposition compared with baseline determinations. In contrast, two of four patients studied while receiving sulfinpyrazone showed decreased platelet deposition. Thus, platelet imaging may be of value for studying platelet physiology in vivo and for assessing platelet-active drugs and the thrombogenicity of prosthetic graft materials in human beings.

  8. Imaging of acute myocardial infarction in pigs with Indium-111 monoclonal antimyosin scintigraphy and MRI

    SciTech Connect

    ten Kate, C.I.; van Kroonenburgh, M.J.; Schipperheyn, J.J.; Doornbos, J.; Hoedemaeker, P.J.; Maes, A.; v.d. Nat, K.H.; Camps, J.A.; Huysmans, H.A.; Pauwels, E.K. )

    1990-07-01

    Indium-111 antimyosin F(ab')2 was used in a series of scintigraphic studies on experimentally induced myocardial infarctions in pigs. Antimyosin distribution recorded by planar images of in vivo pigs and by single photon emission computed tomography (SPECT) of excised hearts delineated areas of myocardial necrosis if infarct volume exceeded 3.3 cm3. Scintigraphic images were compared with magnetic resonance images (MRI) obtained from excised hearts and with photographs of slices of the hearts. Infarct size and localization determined with antimyosin were compared. The MR images, with or without gadolinium-DTPA (Gd-DTPA), of the in vivo pigs were all false-negative; some myocardial wall thinning and high bloodpool signals were visible. Results show that both the antimyosin and the MR technique are specific methods for the visualization of induced myocardial necrosis in this animal model. However, the use of antimyosin is limited to a period ranging from 24 to 72 hours after infarction.

  9. Evaluation of primary lung cancer with indium 111 anti-carcinoembryonic antigen (type ZCE-025) monoclonal antibody scintigraphy

    SciTech Connect

    Krishnamurthy, S.; Morris, J.F.; Antonovic, R.; Ahmed, A.; Galey, W.T.; Duncan, C.; Krishnamurthy, G.T. )

    1990-02-01

    A study was undertaken to test whether indium 111 (111In)-labeled anti-carcinoembryonic antigen (CEA) (type ZCE 025) monoclonal intact antibody (MoAb) would concentrate in primary lung cancer enabling its detection and localization by scintigraphy. The scintigraphic results were correlated with chest radiograph, computed tomograph (CT), bronchoscopy, surgical resection, and tumor CEA analysis. Twenty adult male patients with clinical suspicion of primary lung cancer were studied. Each subject was infused with 4 to 5 mCi of 111In anti-CEA ZCE 025 MoAb, and planar and tomographic scintiphotos were obtained on days 3 and 6 or 7 postinfusion. The scintigraphy was true-positive in 12 of 16 patients with primary lung cancer, eight of nine patients with squamous cell carcinoma, and four of seven with adenocarcinoma; it was true-negative in three of four patients with benign lung disease with an overall accuracy of 75%. In seven patients with confirmed primary lung cancer, but with negative bronchoscopic findings, the scintigraphy was true-positive in four. In 11 patients with definitely positive or suspicious malignancy by bronchoscopy the monoclonal scintigraphy was positive in eight. In true-positive cases, the location and size of the lesion by 111In anti-CEA ZCE 025 MoAb imaging correlated well with CT findings and also tumor mass at surgery. Only one of 12 tumors stained positive for CEA had serum CEA levels greater than 10 ng/ml, indicating nonleakage of the tumor antigen into general circulation in early lung cancer. It is concluded that 111In anti-CEA ZCE 025 MoAb planar and tomographic imaging shows potential to serve as a noninvasive diagnostic test in the evaluation of primary lung cancer. The lung lesion is likely to be malignant if it concentrates 111In anti-CEA ZCE 025 MoAb and benign if it does not.

  10. Indium-111 antimyosin scintigraphy to assess myocardial damage in patients with suspected myocarditis and cardiac rejection

    SciTech Connect

    Carrio, I.; Berna, L.; Ballester, M.; Estorch, M.; Obrador, D.; Cladellas, M.; Abadal, L.; Ginjaume, M.

    1988-12-01

    Indium-111 antimyosin scans were used to assess myocardial damage in patients with suspected myocarditis and cardiac transplant rejection. The calculation of a myocardium to lung ratio (AM index) to quantify antimyosin uptake was performed. AM index in normal subjects (n = 8) at 48 hr postinjection was 1.46 +/- 0.04. In patients with suspected myocarditis (16 studies in 13 patients), AM index was 2.0 +/- 0.5 (p less than 0.001); suggesting a considerable incidence of ongoing cell damage in this group, despite the small proportion of positive right ventricular endomyocardial biopsy (RVbx) (4/13). In patients studied after cardiac transplantation (37 studies in 17 patients), AM indexes correlated with RVbx. In patients with RVbx proven rejection (n = 14), AM index was 1.87 +/- 0.19 (p less than 0.001). In patients with RVbx showing infiltrates but not myocyte damage (n = 13), AM index was 1.80 +/- 0.27 (p = 0.02). In patients with normal RVbx (n = 10), AM index was 1.56 +/- 0.17 (p = NS versus controls; p = 0.001 versus those with positive RVbx). Calculated AM indexes correlated with graded visual analysis of the scans (r = 0.823; p = 0.001). Antimyosin scans are an appropriate method to assess myocardial damage in patients with suspected myocarditis and cardiac rejection.

  11. Combined bone scintigraphy and indium-111 leukocyte scans in neuropathic foot disease

    SciTech Connect

    Schauwecker, D.S.; Park, H.M.; Burt, R.W.; Mock, B.H.; Wellman, H.N.

    1988-10-01

    It is difficult to diagnose osteomyelitis in the presence of neurotrophic osteoarthropathy. We performed combined (99mTc)MDP bone scans and indium-111 (111In) leukocyte studies on 35 patients who had radiographic evidence of neuropathic foot disease and clinically suspected osteomyelitis. The (111In)leukocyte study determined if there was an infection and the bone scan provided the anatomic landmarks so that the infection could be localized to the bone or the adjacent soft tissue. Seventeen patients had osteomyelitis and all showed increased (111In)leukocyte activity localized to the bone, giving a sensitivity of 100%. Among the 18 patients without osteomyelitis, eight had no accumulation of (111In)leukocytes, seven had the (111In)leukocyte activity correctly localized to the soft tissue, two had (111In)leukocyte activity mistakenly attributed to the bone, and one had (111In)leukocyte accumulation in a proven neuroma which was mistakenly attributed to bone. These three false-positive results for osteomyelitis reduced the specificity to 83%. Considering only the 27 patients with a positive (111In)leukocyte study, the combined bone scan and (111In)leukocyte study correctly localized the infection to the soft tissues or bone in 89%. Uninfected neurotrophic osteoarthropathy does not accumulate (111In)leukocytes. We found the combined bone scan and (111In) leukocyte study useful for the detection and localization of infection to soft tissue or bone in patients with neuropathic foot disease.

  12. Indium-111-labeled leukocyte scintigraphy: diagnosis of subperiosteal abscesses complicating osteomyelitis in a child

    SciTech Connect

    Outwater, E.; Oates, E.; Sarno, R.C.

    1988-11-01

    Preoperative /sup 111/In-labeled leukocyte scintigraphy demonstrated extensive subperiosteal abscesses complicating acute bilateral tibial osteomyelitis in a child. Plain radiographs showed only marked soft-tissue swelling; three-phase bone scintigraphy depicted both hot and cold areas consistent with acute osteomyelitis.

  13. Accurate diagnosis of renal transplant rejection by indium-111 platelet imaging despite postoperative cyclosporin therapy

    SciTech Connect

    Collier, B.D.; Adams, M.B.; Kauffman, H.M.; Trembath, L.; Hoffmann, R.G.; Tisdale, P.L.; Rao, S.A.; Hellman, R.S.; Isitman, A.T.

    1988-08-01

    Previous reports indicate that In-111 platelet scintigraphy (IPS) is a reliable test for the early diagnosis of acute post-operative renal transplant rejection (TR). However, the recent introduction of cyclosporin for post-transplantation immunosuppression requires that the diagnostic efficacy of IPS once again be established. Therefore, a prospective IPS study of 73 post-operative renal transplant recipients was conducted. Fourty-nine patients received cyclosporin and 24 patients did not receive this drug. Between these two patient groups, there were no significant differences in the diagnostic sensitivities (0.86 vs 0.80) and specificities (0.93 vs 0.84) with which TR was identified. We conclude that during the first two weeks following renal transplantation the cyclosporin treatment regimen used at our institution does not limit the reliability of IPS as a test for TR.

  14. Postoperative osteomyelitis following implant arthroplasty of the foot: diagnosis with indium-111 white blood cell scintigraphy

    SciTech Connect

    Bakst, R.H.; Kanat, I.O.

    1987-11-01

    Many complications can occur following insertion of silicone elastomer implants into the foot. Postoperative infection may be difficult to distinguish from other conditions such as dislodgment, fracture, ectopic and heterotopic new bone formation, synovitis, and bursitis. White blood cell scintigraphy, in conjunction with the clinical scenario, may prove to be an invaluable tool in the diagnosis of postoperative osteomyelitis, subsequent to implant arthroplasties. 32 references.

  15. In vivo quantitation of platelet deposition on human peripheral arterial bypass grafts using indium-111-labeled platelets. Effect of dipyridamole and aspirin

    SciTech Connect

    Pumphrey, C.W.; Chesebro, J.H.; Dewanjee, M.K.; Wahner, H.W.; Hollier, L.H.; Pairolero, P.C.; Fuster, V.

    1983-03-01

    Indium-111-labeled autologous platelets, injected 48 hours after operation, were used to evaluate the thrombogenicity of prosthetic material and the effect of platelet inhibitor therapy in vivo. Dacron double-velour (Microvel) aortofemoral artery bifurcation grafts were placed in 16 patients and unilateral polytetrafluoroethylene femoropopliteal grafts were placed in 10 patients. Half the patients in each group received platelet inhibitors before operation (dipyridamole, 100 mg 4 times a day) and after operation (dipyridamole, 75 mg, and acetylsalicylic acid, 325 mg 3 times a day); the rest of the patients served as control subjects. Five-minute scintigrams of the graft region were taken with a gamma camera interfaced with a computer 48, 72, and 96 hours after injection of the labeled platelets. Platelet deposition was estimated from the radioactivities of the grafts and expressed as counts per 100 pixels per microcurie injected. Dipyridamole and aspirin therapy significantly reduced the number of platelets deposited on Dacron grafts and prevented platelet accumulation over 3 days. With the small amount of platelet deposition on polytetrafluoroethylene femoropopliteal artery grafts even in control patients, platelet inhibitor therapy had no demonstrable effect on platelet deposition on these grafts. It is concluded that (1) platelet deposition on vascular grafts in vivo can be quantitated by noninvasive methods, and (2) dipyridamole and aspirin therapy reduced platelet deposition on Dacron aortofemoral artery grafts.

  16. Indium-111-labeled platelets: effect of heparin on uptake by venous thrombi and relationship to the activated partial thromboplastin time

    SciTech Connect

    Fedullo, P.F.; Moser, K.M.; Moser, K.S.; Konopka, R.; Hartman, M.T.

    1982-09-01

    The goal of heparin thepapy in deep vein thrombosis is to prevent thrombus extension. The relationship between thrombus extension and the results of coagulation tests used to monitor heparin thepapy is unclear. To expose this relationship, we studied the effect of several heparin regimens on the accretion of indium-111-labeled platelets on fresh venous thrombi, as detected by gamma imaging, and monitored the activated partial thromboplastin time (APTT). Six dogs were treated with a 300-U/kg bolus of heparin followed by a 90-U/kg/hour heparin infusion, a dose of heparin sufficient to increase the APTT to levels greater than eight times baseline (APTT ratio); platelet accretion (thrombus imaging) occurred only after the heparin effect was reversed with protamine sulfate. Nineteen dogs were treated with a 150-U/kg bolus of heparin followed by a 4-hour, 45-U/kg/hour heparin infusion; a thrombus was demonstrated only after protamine injection in 12 (mean APTT ratio 1.3 +/- 0.19) and before protamine injection in seven. In thirteen of these 19 dogs, 30 minutes separated the platelet injection from heparin therapy, while in six this duration was less than 30 minutes. In four of these six dogs, thrombi were demonstrated before protamine therapy and at APTT ratios greater than 3.0. Finally, 10 dogs were treated with a 100-U/kg bolus followed by a 3-hour, 50-U/kg/hour heparin infusion, after which the APTT was allowed to return to baseline values spontaneously. In all 10 dogs, a thrombus was demonstrated only after cessation of the heparin infusion, and at a mean APTT ratio of 1.4 +/- 0.15 times baseline. These results suggest that, except with very early platelet injection, platelet accretion by thrombi is consistently inhibited by heparin at APTT ratios greater than 2.5.

  17. Detection of rejection of canine orthotopic cardiac allografts with indium-111 lymphocytes and gamma scintigraphy

    SciTech Connect

    Eisen, H.J.; Rosenbloom, M.; Laschinger, J.C.; Saffitz, J.E.; Cox, J.L.; Sobel, B.E.; Bolman, R.M. III; Bergmann, S.R.

    1988-07-01

    Previous studies have demonstrated the feasibility of detecting canine heterotopic cardiac allograft rejection scintigraphically after administration of 111In lymphocytes. To determine whether the approach is capable of detecting rejection in orthotopic cardiac transplants in which labeled lymphocytes circulating in the blood pool may reduce sensitivity, the present study was performed in which canine orthotopic cardiac transplants were evaluated in vivo. Immunosuppression was maintained with cyclosporine A (10-20 mg/kg/day) and prednisone (1 mg/kg/day) for 2 wk after transplantation. Subsequently, therapy was tapered. Five successful allografts were evaluated scintigraphically every 3 days after administration of 100-350 microCi 111In autologous lymphocytes. Correction for labeled lymphocytes circulating in the blood pool, but not actively sequestered in the allografts was accomplished by administering 3-6 mCi 99mTc autologous erythrocytes and employing a previously validated blood-pool activity correction technique. Cardiac infiltration of labeled lymphocytes was quantified as percent indium excess (%IE), scintigraphically detectable 111In in the transplant compared with that in blood, and results were compared with those of concomitantly performed endomyocardial biopsy. Scintigraphic %IE for hearts not undergoing rejection manifest histologically was 0.7 +/- 0.4. Percent IE for rejecting hearts was 6.8 +/- 4.0 (p less than 0.05). Scintigraphy detected each episode of rejection detected by biopsy. Scintigraphic criteria for rejection (%IE greater than 2 s.d. above normal) were not manifest in any study in which biopsies did not show rejection. Since scintigraphic results with 111In-labeled lymphocytes were concordant with biopsy results in orthotopic cardiac transplants, noninvasive detection of graft rejection in patients should be attainable with the approach developed.

  18. Effects of antithrombotic drugs in patients with left ventricular thrombi: assessment with indium-111 platelet imaging and two-dimensional echocardiography

    SciTech Connect

    Stratton, J.R.; Ritchie, J.L.

    1984-03-01

    Patients with left ventricular thrombi not caused by recent myocardial infarction were prospectively studied by indium-111 platelet imaging and two-dimensional echocardiography to determine the reproducibility of these techniques and the short-term effects of sulfinpyrazone (200 mg four times daily), aspirin (325 mg three times daily) plus dipyridamole (75 mg three times daily), and full-dose warfarin. At baseline, all patients underwent indium-111 platelet imaging and echocardiography, and the results were positive for thrombus. In six patients on no antithrombotic drug therapy, repeat platelet scans and echocardiographic studies at 6.0 +/- 3.3 weeks remained positive and were unchanged. In seven patients studied on sulfinpyrazone, three platelet scans became negative, two became equivocal, and two were unchanged; the presence and size of thrombus was constant by echocardiography in all seven patients. Of the six patients studied on aspirin plus dipyridamole, one platelet scan became negative, those of three became equivocal, and two were unchanged; all echocardiographic findings remained positive, but one patient had decreased thrombus size. Among four warfarin-treated patients, three had resolution of platelet deposition and one was unchanged; by echocardiography, thrombus resolved in one patient, was decreased in size in one, and was unchanged in two. We conclude that, in the absence of antithrombotic drug therapy, platelet imaging and echocardiographic findings are stable in patients with left ventricular thrombi not caused by recent myocardial infarction. Sulfinpyrazone, aspirin plus dipyridamole, and warfarin all interrupt platelet deposition in some patients with chronic left ventricular thrombi.

  19. Splenic dynamics of indium-111 labeled platelets in idiopathic thrombocytopenic purpura

    SciTech Connect

    Syrjaelae, M.T.Sa.; Savolainen, S.; Nieminen, U.; Gripenberg, J.; Liewendahl, K.; Ikkala, E. )

    1989-09-01

    Splenic dynamics of {sup 111}In-labeled platelets and platelet-associated IgG in 33 patients with idiopathic thrombocytopenic purpura (ITP) were studied. Two half-lives were calculated for the biexponential splenic time-activity curve after i.v. injection of {sup 111}In-labeled platelets. There was no difference in the mean half-life of the rapid component of the splenic curve (ST1) when patients with negative or slightly positive platelet suspension immunofluorescence test (PSIFT) were compared to those with strongly positive PSIFT (3.0 {plus minus} 0.7 min vs. 3.6 {plus minus} 0.4, p greater than 0.05). Mean half-life of the slow component of the splenic curve (ST2) was found to be longer in patients with a strongly positive than a negative or weakly positive PSIFT (26 {plus minus} 5 min vs. 13.2 {plus minus} 1.0 min, p less than 0.01). It seems that determination of the two components of the splenic time-activity curve provides a useful method for studying platelet kinetics in ITP.

  20. Comparison of indium-111 scintigraphy and colonoscopy with histologic study in children for evaluation of colonic chronic inflammatory bowel disease

    SciTech Connect

    Tolia, V.; Kuhns, L.R.; Chang, C.H.; Slovis, T.L. )

    1991-04-01

    Indium-111 leukocyte scanning and colonoscopy were performed in 19 children and adolescents with chronic inflammatory bowel disease to study the correlation of evaluation between these two diagnostic modalities in comparison to histologic study for colonic disease. Seven patients had ulcerative colitis, 10 had Crohn's disease, and two patients had no specific diagnosis after evaluation. The sensitivity of indium-111 scan was 18%, specificity was 62.5%, and accuracy for diagnosing colonic disease was only 37%. In comparison, sensitivity and specificity for colonoscopy were 100 and 57%, respectively. Furthermore, accuracy with colonoscopy was 84%. The authors data suggest that the usefulness of scans is limited to patients in whom standard diagnostic procedures are contraindicated. In addition, it is essential to confirm the visual diagnostic impression on colonoscopy with histologic study.

  1. The use of indium-111 labeled platelet scanning for the detection of asymptomatic deep venous thrombosis in a high risk population

    SciTech Connect

    Siegel, R.S.; Rae, J.L.; Ryan, N.L.; Edwards, C.; Fortune, W.P.; Lewis, R.J.; Reba, R.C. )

    1989-11-01

    Five hundred indium-111 labeled platelet imaging studies (387 donor and 113 autologous) were performed postoperatively in 473 patients who had undergone total hip replacement, total knee replacement, or internal fixation of a hip fracture to detect occult deep venous thrombosis. All patients had been anticoagulated prophylactically with aspirin, warfarin sodium (Coumadin), or dextran. Thirty-four possible cases of proximal deep venous thrombosis were identified in 28 asymptomatic patients. To verify the scan results, 31 venograms were performed in 25 patients (three refused). In 21 of 31 cases, totally occlusive thrombi were detected; in 5 cases, partially occlusive thrombi were detected; in 5 cases, no thrombus was seen. No patient who had a negative scan nor any patient who had a verified positive scan (and received appropriate heparin therapy) subsequently developed symptoms or signs of pulmonary embolism. One hundred forty-one indium study patients also underwent Doppler ultrasonography/impedance plethysmography (Doppler/IPG) as a comparative non-invasive technique. In 137 cases, the results of the indium study and Doppler/IPG studies were congruent. The indium study had no false negative results that were detected by Doppler/IPG. No patient had any clinically evident toxicity. These results suggest that indium-111 labeled platelet scanning is a safe, noninvasive means for identifying DVT in high risk patients.

  2. A quantitative method to measure human platelet chemotaxis using indium-111-oxine-labeled gel-filtered platelets

    SciTech Connect

    Lowenhaupt, R.W.; Silberstein, E.B.; Sperling, M.I.; Mayfield, G.

    1982-12-01

    Human blood platelets have been shown to migrate directionally and specifically toward collagen in plasma in vitro. We have developed a new system to monitor this behavior using a linear 7-compartment chamber with /sup 111/In-oxine-labeled gel-filtered platelets. The compartments are separated by various Nuclepore and Millipore filter membranes. Radiolabeled platelets suspended in plasma are placed in the central compartment and the other compartments are filled with platelet-free plasma. When collagen is added to an end compartment, platelets migrate toward that end. The degree of this directed movement or chemotaxis can be measured by counting the radioactivity of the contents of each compartment and then comparing the counts from radiolabeled platelets that have moved to the end that holds the chemotactic inducer with those that have randomly migrated to the opposite end, containing only plasma. This assay system allows quantitative comparisons between the chemotaxis-inducing abilities of different substances and permits the study of soluble materials. Experiments to determine the optimal conditons for the procedure are reported, and the advantages of this new method for the investigation of platelet chemotaxis and the identification of chemotaxins are discussed.

  3. Clinical Utility of Indium 111–Labeled White Blood Cell Scintigraphy for Evaluation of Suspected Infection

    PubMed Central

    Lewis, Sarah S.; Cox, Gary M.; Stout, Jason E.

    2014-01-01

    Background  We sought to characterize the clinical utility of indium 111 (111In)–labeled white blood cell (WBC) scans by indication, to identify patient populations who might benefit most from this imaging modality. Methods  Medical records for all patients who underwent 111In-labeled WBC scans at our tertiary referral center from 2005 to 2011 were reviewed. Scan indication, results, and final diagnosis were assessed independently by 2 infectious disease physicians. Reviewers also categorized the clinical utility of each scan as helpful vs not helpful with diagnosis and/or management according to prespecified criteria. Cases for which clinical utility could not be determined were excluded from the utility assessment. Results  One hundred thirty-seven scans were included in this analysis; clinical utility could be determined in 132 (96%) cases. The annual number of scans decreased throughout the study period, from 26 in 2005 to 13 in 2011. Forty-one (30%) scans were positive, and 85 (62%) patients were ultimately determined to have an infection. Of the evaluable scans, 63 (48%) scans were deemed clinically useful. Clinical utility varied by scan indication: 111In-labeled WBC scans were more helpful for indications of osteomyelitis (35/50, 70% useful) or vascular access infection (10/15, 67% useful), and less helpful for evaluation of fever of unknown origin (12/35, 34% useful). Conclusions  111In-labeled WBC scans were useful for patient care less than half of the time at our center. Targeted ordering of these scans for indications in which they have greater utility, such as suspected osteomyelitis and vascular access infections, may optimize test utilization. PMID:25734155

  4. Effect of different aspirin doses on arterial thrombosis after canine carotid endarterectomy: a scanning electron microscope and indium-111-labeled platelet study

    SciTech Connect

    Ercius, M.S.; Chandler, W.F.; Ford, J.W.; Swanson, D.P.; Burke, J.C.

    1984-02-01

    Although it is widely accepted that aspirin inhibits platelet aggregation in arterial thrombosis, the appropriate dosage of aspirin remains quite controversial. The purpose of this study was to determine the effect of different doses of aspirin (0.5 mg/kg vs. 10 mg/kg) on mural thrombus formation after carotid endarterectomy. Eighteen hours after oral aspirin administration, 20 endarterectomies were performed on mongrel dogs with the use of the operating microscope. Blood flow was then restored for 3 hours and the vessels were prepared for investigation with the scanning electron microscope. Ten endarterectomies were also performed on unmedicated dogs as controls. Five minutes before vessel unclamping, autologous indium-111-labeled platelets were administered intravenously, and the endarterectomized portions of the vessels were studied with a gamma counter system after harvesting. Group 1, the control group, revealed extensive mural thrombus consisting of platelet aggregates, fibrin, red blood cells, and white blood cells. Six of the 10 vessels in Group 2, premedicated with 0.5 mg of aspirin per kg, demonstrated varying amounts of mural thrombus. Group 3 (10 vessels), premedicated with 10 mg of aspirin per kg, revealed a platelet monolayer completely covering the exposed vessel wall media, with scattered white blood cells and infrequent fine fibrin strands overlying the platelet surface. The mean (+/- SD) radioactivity per group expressed as counts/minute/mm2 was: Group 1--2055.3 +/- 1905.5, log . 7.253 +/- 0.926; Group 2--1235.6 +/- 1234.3, log . 6.785 +/- 0.817; Group 3--526 +/- 433.06, log . 5.989 +/- 0.774.

  5. Analysis of indium-111 platelet kinetics and imaging in patients with aortic grafts and abdominal aortic aneurysms

    SciTech Connect

    Hanson, S.R.; Kotze, H.F.; Pieters, H.; Heyns, A.D. )

    1990-11-01

    To quantitatively characterize processes of platelet thrombus formation in vivo, the kinetics and incorporation into thrombus of autologous In-111-labeled platelets were compared in six patients with aortic aneurysms and in seven patients with prosthetic aortic grafts. Although platelet survival was comparably shortened in both patient groups (mean, 5.8 days), the maximum radioactivity as determined by gamma camera imaging was higher in the aneurysms than in the grafts (3.3% +/- 1.6% vs. 1.6% +/- 1.1%, p = 0.05). Maximum In-111 uptake was also attained more quickly in the aneurysm patients (2.3 +/- 0.8 days vs. 3.5 +/- 1.3 days; p = 0.07). The experimental platelet kinetic and imaging data were subsequently evaluated by compartmental analysis to estimate both normal and disease-related components of platelet destruction. This analysis indicated that deposited platelet radioactivity had a longer residence time on grafts (2.9 +/- 1.7 days vs. 1.4 +/- 0.9 days, p = 0.07) but accumulated at a faster rate in aneurysms (5.0% +/- 3.4% per day vs. 1.4% +/- 0.9% per day, p = 0.02). As determined by imaging, only a proportion of increased platelet destruction was specifically due to the aneurysms (55% +/- 38%) or grafts (17% +/- 11%, p = 0.03). This result indicates additional components of platelet destruction unrelated to graft and aneurysm thrombus formation which, in some graft patients, may reflect a greater severity of vascular disease or other mechanisms causing a preferential shortening of platelet survival. Thus, the analytical approach described may be a useful one for discriminating components of in vivo platelet utilization including platelet removal due to normal hemostatic and senescent mechanisms, localized thrombus formation, and more generalized vascular disease.

  6. Detection of a prosthetic aortic valvular abscess with indium-111-labeled leukocytes

    SciTech Connect

    Oates, E.; Sarno, R.C.

    1988-10-01

    An unsuspected annular abscess at the base of a prosthetic aortic valve in a patient with endocarditis was identified by indium-111-labeled leukocyte scintigraphy alone. This highly sensitive and specific technique expediently demonstrated the surgically proven inflammatory focus.

  7. A new technique for quantification of platelet thrombosis on bovine pericardial valve prostheses (Ionescu-Shiley) in calves with indium-111 labeled platelets

    SciTech Connect

    Dewanjee, M.K.; Solis, E.E.; Mackey, S.; Chesebro, J.H.; Didisheim, P.; Edwards, W.D.; Zollman, P.E.; Kaye, M.P.

    1985-05-01

    Platelet thrombosis on components of tissue valve prosthesis explanted from Holstein calves was quantified with In-111-labeled autologous platelets. Twenty-eight calves were implanted with 25 mm bovine pericardial valve prostheses in mitral annulus and killed 1, 14, 30 and 90 days post-implantation. Twenty-four hours before killing 350-450 ..mu..Ci of autologous In-111 platelets were administered intravenously. Components of the explanted valve were imaged with a gamma camera. Mean (+- SD) value of platelet deposition (PlX10/sup 5//mm/sup 2/) on four sections of each leaflet (free edge: FE, central zone: CZ, flexion zone: FZ, attachment zone: AZ) was calculated from platelet count, radioactivity in blood, leaflet sections and area of leaflet sections. With fibrous ingrowth in sewing ring the tissue valve becomes less thrombogenic at 30 days post-implantation; with increase in calcification platelet thrombosis also increases in central zone of leaflet at 30 and 90 days.

  8. Deep venous thrombophlebitis: detection with 4-hour versus 24-hour platelet scintigraphy

    SciTech Connect

    Seabold, J.E.; Conrad, G.R.; Ponto, J.A.; Kimball, D.A.; Frey, E.E.; Ahmed, F.; Coughlan, J.D.; Jensen, K.C.

    1987-11-01

    Thirty-one nonheparinized patients with suspected deep venous thrombophlebitis (DVT) underwent contrast venography and indium-111 platelet scintigraphy (In-111 PS). Venography permitted identification of acute DVT in 12 of 31 cases (39%). One additional patient was considered to have acute DVT despite nonconclusive venography results. In-111 PS results were positive at 4 hours in nine of 13 cases (69%) and at 24 hours in 12 of 13 cases (92%). Two of four patients with false-negative 4-hour In-111 PS studies had received warfarin. Thus, the sensitivity of 4-hour In-111 PS in patients not receiving anticoagulants was 82%. Venography results were negative for acute DVT in 18 cases, and 4-hour In-111 PS studies were negative or equivocal in each. In-111 PS is an alternative to contrast venography for detecting acute DVT. If 4-hour In-111 PS results are positive, anticoagulation can be initiated. Delayed images are necessary if the 4-hour images are negative or equivocal.

  9. Indium-111 leukocyte scanning and fracture healing

    SciTech Connect

    Mead, L.P.; Scott, A.C.; Bondurant, F.J.; Browner, B.D. )

    1990-01-01

    This study was undertaken to determine the specificity of indium-111 leukocyte scans for osteomyelitis when fractures are present. Midshaft tibial osteotomies were performed in 14 New Zealand white rabbits, seven of which were infected postoperatively with Staphylococcus aureus per Norden's protocol. All 14 rabbits were scanned following injection with 75 microCi of indium 111 at 72 h after osteotomy and at weekly intervals for 4 weeks. Before the rabbits were killed, the fracture sites were cultured to document the presence or absence of infection. The results of all infected osteotomy sites were positive, whereas no positive scans were found in the noninfected osteotomies. We concluded from this study that uncomplicated fracture healing does not result in a positive indium-111 leukocyte scan.

  10. Tumour scanning with indium-111 dihaematoporphyrin ether.

    PubMed Central

    Quastel, M. R.; Richter, A. M.; Levy, J. G.

    1990-01-01

    Photofrin II (dihaematoporphyrin ether/ester, DHE) was labelled with indium-111 and its biodistribution in tumour bearing mice compared with that of 111In chloride. The uptake and clearance of 111In labelled DHE differed markedly from that of indium-111 chloride in that the former was not taken up by the tissues as much as the latter. Scintillation scanning with a gamma-camera showed marked uptake of both 111In agents at the site of the tumour, but a much lower tissue background (excluding the abdominal organs) for the mice given 111In DHE. Tumour:muscle ratios of dissected tissues were 2-3 times higher in 111In DHE treated animals as compared to the uptake of 111In chloride. There was a distinct difference in the pattern of distribution of the two 111In preparations in the tissues. The major accumulation of 111In chloride was in the kidneys, whereas the highest uptake of 111In DHE was in the liver, the organ in which unlabelled porphyrins accumulate. Extraction and testing of materials from tumours of 111In DHE treated animals indicated that most of the tumour extractable 111In had remained associated with the porphyrin in vivo up to 4 days after injection. Images Figure 1 PMID:2147858

  11. Aspirin inhibition of platelet deposition at angioplasty sites: demonstration by platelet scintigraphy

    SciTech Connect

    Cuningham, D.A.; Kumar, B.; Siegel, B.A.; Gilula, L.A.; Totty, W.G.; Welch, M.J.

    1984-05-01

    In-111 platelet scintigraphy was used to evaluate the effects of prior aspirin administration on the accumulation of In-111-labeled autologous platelets at sites of arterial injury resulting from iliac, femoral, or popliteal transluminal angioplasty in a nonrandomized study of 17 men. The degree of platelet localization at angioplasty sites was significantly less in nine men who had received aspirin in varying doses within the 4 days before angioplasty than in eight men who had not received aspirin for at least two weeks. The results suggest that aspirin treatment before angioplasty limits the early platelet deposition at the angioplasty site in men.

  12. Clinical imaging with indium-111 leukocytes: uptake in bowel infarction

    SciTech Connect

    Gray, H.W.; Cuthbert, I.; Richards, J.R.

    1981-08-01

    Leukocytes labeled with indium-111 accumulated in an area of small-bowel infarction, mimicking a paracolic abscess. Evidence of subacute bowel obstruction should alert the nuclear medicine physician to the former possibility.

  13. Evaluation of indium-111-labeled antifibrin monoclonal antibody for the diagnosis of venous thrombotic disease

    SciTech Connect

    De Faucal, P.; Peltier, P.; Planchon, B.; Dupas, B.; Touze, M.D.; Baron, D.; Scaible, T.; Berger, H.J.; Chatal, J.F. )

    1991-05-01

    The potential advantage of using {sup 111}In-antifibrin ({sup 111}In-AF) monoclonal antibody for the diagnosis of deep venous thrombosis (DVT) was studied in 44 patients with suspected DVT (27 underwent heparin therapy before {sup 111}In-AF injection). All patients had contrast venography (considered as the gold standard) and {sup 111}In-AF scintigraphy within 24 hr. Two to 3 mCi of {sup 111}In-AF were injected intravenously, and planar scintigraphy of the limbs was recorded within 10 min (17 times), 3 hr (44 times), and 18 hr (39 times). Indium-111-AF images were then interpreted without knowledge of the results of the other examinations. The DVT diagnostic accuracy of {sup 111}In-AF was greater when interpretation was based on images recorded at different time periods after injection. Indium-111-AF sensitivity for diagnosis of DVT was 85% (29/34) and was not apparently decreased by heparin therapy. None of the 10 patients with negative contrast venography had a positive {sup 111}In-AF scan. The results demonstrate the importance of recording serial images and the excellent accuracy of {sup 111}In-AF for diagnosing DVT.

  14. Edwardsiella tarda Endocarditis Confirmed by Indium-111 White Blood Cell Scan: An Unusual Pathogen and Diagnostic Modality

    PubMed Central

    Litton, Kayleigh M.; Rogers, Bret A.

    2016-01-01

    Edwardsiella tarda is a freshwater marine member of the family Enterobacteriaceae which often colonizes fish, lizards, snakes, and turtles but is an infrequent human pathogen. Indium-111- (111In-) labeled white blood cell (WBC) scintigraphy is an imaging modality which has a wide range of reported sensitivity and specificity (from 60 to 100% and from 68 to 92%, resp.) for diagnosing acute and chronic infection. We describe a case of suspected E. tarda prosthetic aortic valve and mitral valve endocarditis with probable vegetations and new mitral regurgitation on transthoracic and transesophageal echocardiograms which was supported with the use of 111In-labeled WBC scintigraphy. PMID:26885418

  15. Edwardsiella tarda Endocarditis Confirmed by Indium-111 White Blood Cell Scan: An Unusual Pathogen and Diagnostic Modality.

    PubMed

    Litton, Kayleigh M; Rogers, Bret A

    2016-01-01

    Edwardsiella tarda is a freshwater marine member of the family Enterobacteriaceae which often colonizes fish, lizards, snakes, and turtles but is an infrequent human pathogen. Indium-111- ((111)In-) labeled white blood cell (WBC) scintigraphy is an imaging modality which has a wide range of reported sensitivity and specificity (from 60 to 100% and from 68 to 92%, resp.) for diagnosing acute and chronic infection. We describe a case of suspected E. tarda prosthetic aortic valve and mitral valve endocarditis with probable vegetations and new mitral regurgitation on transthoracic and transesophageal echocardiograms which was supported with the use of (111)In-labeled WBC scintigraphy. PMID:26885418

  16. Indium-111-Photofrin-II scintillation scan

    SciTech Connect

    Origitano, T.C.; Karesh, S.M.; Reichman, O.H.; Henkin, R.E.; Caron, M.J.

    1989-04-01

    Photodynamic therapy is under intense investigation as an adjuvant treatment for malignant glial tumors of the central nervous system. Photofrin-II (HpD-II) is currently the most actively investigated photosensitizing agent. A crucial issue regarding the safe and efficacious usage of HpD-II-based photodynamic therapy is the individual in vivo kinetics of tumor uptake and retention, compared with normal brain clearance. The optimal time for photoactivation of sensitized tumor must be known to ensure a high target-to-nontarget ratio, resulting in the maximal tumor destruction while preserving normal brain. Our laboratory developed a radionuclide scan based on 111indium (111In)-labeled HpD-II to evaluate HpD-II localization and clearance noninvasively within a canine model of intracerebral gliosarcoma. Synthesis of the 111In-HpD-II complex in greater than 90% yield is achieved by a simple, rapid labeling method. Radiochemical purity and stability were verified by high-performance liquid chromatography. Using the canine model of intracerebral gliosarcoma, we followed the uptake of 111In-HpD-II in tumors with serial scintillation scanning. Localization of the tumor by 111In-HpD-II has been verified by contrast-enhanced computed tomographic scan followed by gross and histological examination of the enhancing brain region. Total body biodistribution of 111In-HpD-II at various times after injection has been evaluated. The ratio of uptake in tumor compared with surrounding brain peaked at 72 hours after injection. The knowledge of regional distribution and concentration of a photosensitizing agent within a tumor mass and surrounding brain allows for the most efficacious timing and localization of a photoactivating source.

  17. Persistent uptake of indium-111-antimyosin monoclonal antibody in patients with myocardial infarction

    SciTech Connect

    Matsumori, A.; Yamada, T.; Tamaki, N.; Kawai, C.; Watanabe, Y.; Yonekura, Y.; Endo, K.; Konishi, J.; Yoshida, A.; Tamaki, S. )

    1990-11-01

    Indium-111(111In)-antimyosin scintigraphy was investigated in 27 patients with myocardial infarction. {sup 111}In-antimyosin Fab was administered intravenously, and planar and single photon emission computed tomographic images were obtained 48 hours later. Uptake of {sup 111}In-antimyosin was present in 9 of 10 patients (90%) studied within 6 days of infarction. During the second week positive scans were seen in 16 of 16 patients (100%) including 13 (81%) who had normal creatine kinase levels. The mechanism of persistent positive antimyosin images in the subacute stage of myocardial infarction remains to be clarified. {sup 111}In-antimyosin scintigraphy may be useful as a noninvasive method for the detection of myocardial injury late and early after a suspected acute myocardial infarction.

  18. The role of indium-111 antimyosin (Fab) imaging as a noninvasive surveillance method of human heart transplant rejection

    SciTech Connect

    De Nardo, D.; Scibilia, G.; Macchiarelli, A.G.; Cassisi, A.; Tonelli, E.; Papalia, U.; Gallo, P.; Antolini, M.; Pitucco, G.; Reale, A. )

    1989-09-01

    The identification of rejection after heart transplantation in patients receiving cyclosporine immunosuppressive therapy requires the endomyocardial biopsy, an invasive method associated with a finite morbidity. To evaluate the role of indium-111 antimyosin (Fab) scintigraphy as a noninvasive surveillance method of heart transplant rejection, the Fab fragment of murine monoclonal antimyosin antibodies labeled with indium-111 was administered intravenously in 30 scintigraphic studies to 10 consecutive heart transplant recipients. Endomyocardial biopsy specimens were obtained 72 hours after each scintigraphic study. Nineteen scintigraphic studies had negative findings; no false negative finding was obtained. Eleven antimyosin scintigraphic studies had positive findings, and in these studies endomyocardial biopsy revealed mild rejection in two cases, moderate acute rejection with myocyte necrosis in two cases, myocyte necrosis as a consequence of ischemic injury in six cases, and possibly cytotoxic damage in one case. Antimyosin scintigraphy may represent a reliable screening method for the surveillance of heart transplant patients. In the presence of a negative finding from antimyosin scintigraphy, it may be possible to avoid endomyocardial biopsy. Conversely, in patients who have a positive finding from antimyosin scintigraphy, the endomyocardial biopsy is mandatory to establish the definitive diagnosis by histologic examination of the myocardium.

  19. Indium-111-leukocyte imaging in acute cholecystitis

    SciTech Connect

    Fink-Bennett, D.; Clarke, K.; Tsai, D.; Nuechterlein, P.; Gora, G. )

    1991-05-01

    Eleven patients with suspected acute cholecystitis underwent sequential {sup 99}mTc-iminodiacetic derivative (IDA) and {sup 111}In-white blood cell (WBC) imaging to determine if {sup 111}In-WBCs accumulate within an acutely inflamed hemorrhagic gallbladder wall and, thus, could be employed as a reasonable alternative to {sup 99}mTc-IDA scintigraphy in detecting acute cholecystitis. Seven patients had surgically confirmed acute cholecystitis. Of these cases, five had a true-positive {sup 99}mTc-IDA and {sup 111}In-WBC, one an indeterminate {sup 111}In-WBC and true-positive {sup 99}mTc-IDA, and one a true-positive {sup 111}In-WBC and false-negative {sup 99}mTc-IDA scan. The remaining four patients did not have acute cholecystitis. All visualized their gallbladder within 1 hr after {sup 99}mTc-IDA administration and none had {sup 111}In-WBC gallbladder wall uptake. Both {sup 111}In-WBC and {sup 99}mTc-IDA scintigraphy accurately detected acute cholecystitis: hepatobiliary scintigraphy demonstrated a cystic duct obstruction and {sup 111}In-WBC imaging detected the inflammatory infiltrate within the gallbladder wall. The sensitivity and specificity of each was 86% and 100%, respectively.

  20. Indium-111 labeled anti-melanoma monoclonal antibodies

    DOEpatents

    Srivastava, S.C.; Fawwaz, R.A.; Ferrone, S.

    1984-04-30

    A monoclonal antibody to a high molecular weight melanoma-associated antigen was chelated and radiolabeled with indium-111. This material shows high affinity for melanoma and thus can be used in the detection, localization and imaging of melanoma. 1 figure.

  1. Use of indium-111-labeled cells in measurement of cellular dynamics of experimental cardiac allograft rejection

    SciTech Connect

    Oluwole, S.; Wang, T.; Fawwaz, R.; Satake, K.; Nowygrod, R.; Reemtsma, K.; Hardy, M.A.

    1981-01-01

    This study evaluates the kinetics and utility of infused indium-111-labeled cells in detecting rejection in ACI to Lewis rat heart allografts. Syngeneic leukocytes, lymph node lymphocytes, and platelets were isolated and labeled with indium-111 (/sup 111/In) oxine, respectively, and were infused i.v. into Lewis rats carrying beating ACI or syngeneic hearts from post-transplant days 0 to 6. Recipients were imaged serially at 24 hr after infusion of labeled cells followed by excision of both native and transplanted hearts for direct isotope count. Labeled leukocytes accumulative progressively in the allograft with the scan becoming positive by post-transplant day 4. The ratio of allograft to native heart isotope counts rose from 1.25 on day 1 to 10.07 (P less than 0.0001) on day 7. The Lewis recipients infused with labeled lymphocytes showed a positive scan on days 6 and 7 whereas the allograft to native heart isotope count ratio rose from 0.97 on day 1 to 5.33 (P less than 0.001) on day 7. Recipients infused with /sup 111/In-labeled platelets showed a positive scan on days 5 to 7 and the allograft to native heart isotope count ratio rose sharply from 2.56 on day 4 to 16.98 (P less than 0.005) on day 7. Syngeneic heart grafts failed to demonstrate significant accumulation of any of the labeled cell population. These studies confirm the importance of nonlymphocytic cells in cellular rejection, evaluate the kinetics of graft invasion by the various cell types, and suggest that the techniques used afford a method for a safe and an early detection of allograft rejection.

  2. Acute myocardial infarct imaging with indium-111-labeled monoclonal antimyosin Fab

    SciTech Connect

    Khaw, B.A.; Yasuda, T.; Gold, H.K.; Leinbach, R.C.; Johns, J.A.; Kanke, M.; Barlai-Kovach, M.; Strauss, H.W.; Haber, E.

    1987-11-01

    Indium-111 monoclonal antimyosin Fab scintigraphy was used to detect myocardial necrosis in 52 of 54 patients (96.3%) with acute myocardial infarction. Infarcts were visualized when coronary arteries were persistently occluded (n = 10), became patent after thrombolysis (n = 33), or became patent after spontaneous reperfusion (n = 7). Posteroinferolateral visualizations were obtained in two patients with clinical and enzymatic evidence of infarction but normal electrocardiograms. Of the two patients in whom no infarcts were visualized, one had an anterior myocardial infarct. This patient underwent successful thrombolytic therapy, with attendant minimization of creatine kinase release. The other patient had a small, nonreperfused inferior myocardial infarct. Five patients with a history of remote infarction and acute necrosis showed antimyosin uptake only in regions concordant with the acute episodes of infarction, and radiolabeled antimyosin Fab localized in neither old infarcts nor normal, noninfarcted myocardium. Antimyosin Fab scintigraphy, thus, appears to be a highly specific means of delineating necrotic myocardium, at least in this limited and selected group of patients.

  3. Scintigraphic detection of bone and joint infections with indium-111-labeled nonspecific polyclonal human immunoglobulin G

    SciTech Connect

    Oyen, W.J.; Claessens, R.A.; van Horn, J.R.; van der Meer, J.W.; Corstens, F.H. )

    1990-04-01

    The utility of indium-111-({sup 111}In) labeled immunoglobulin G (IgG) to detect infection of bone and adjacent tissues was investigated. Proof of infection was obtained by cultures taken at surgery. All 32 patients showed focally increased uptake on the technetium-99m- (99mTc) methylene diphosphonate (MDP) skeletal scintigraphies. Labeled immunoglobulin correctly identified presence, location, extent and soft-tissue involvement of the suspected inflammatory site. In these patients, focally increasing accumulation was noted over 48 hr. Discrimination between infection and sterile inflammatory lesions was not possible. Two fractures, 6-mo-old, and an aseptic loosening of a total-hip prosthesis were not visualized. Side effects after the immunoglobulin administration were not observed. Radiolabeled immunoglobulin is a new and safe radiopharmaceutical for the investigation of infectious bone and joint disease. The sensitivity of this agent appears at least as high as that of labeled leukocytes. However, labeled immunoglobulin can easily be prepared in every nuclear medicine department.

  4. Indium 111-labeled white blood cell scans after vascular prosthetic reconstruction

    SciTech Connect

    Sedwitz, M.M.; Davies, R.J.; Pretorius, H.T.; Vasquez, T.E.

    1987-11-01

    The clinical value of indium 111-labeled white blood cell (WBC) scanning done after vascular graft procedures was investigated to differentiate noninfectious postoperative inflammation associated with graft incorporation from early prosthetic graft infection. Indium 111-labeled WBC scans were initially obtained in 30 patients before discharge from the hospital and during the subsequent follow-up period (334 days). Fourteen of 30 patients (47%) had normal predischarge scans that included all 10 patients who had grafts confined to the abdomen and 4 of 20 patients (20%) who had grafts arising or terminating at the femoral arteries (p less than 0.05). Sixteen of 30 patients (53%) discharged with abnormal initial indium 111 WBC scans underwent serial scanning until the scan normalized or a graft complication developed. All of the 16 patients had grafts involving the groin region. Abnormal indium 111 uptake in the femoral region continued for a mean 114 days without the development of prosthetic graft infections. The sensitivity of indium 111-labeled WBC scans for detecting wound complications was 100%, whereas the specificity was 50%. Thus, the accuracy of the test was only 53%. We conclude that (1) abnormal indium 111 WBC scans are common after graft operations involving the groin region but are unusual after vascular procedures confined to the abdomen, and (2) in the absence of clinical suspicion, the indium 111-labeled WBC scan does not reliably predict prosthetic graft infection because of the low specificity of the test in the early postoperative period.

  5. Clinical imaging with indium 111 oxine-labeled leukocyte scan: review and case report

    SciTech Connect

    Simon, W.H.; Joseph, W.S.

    1988-04-01

    The clinical use and mechanisms of action of technetium 99m pyrophosphate, gallium 67 citrate, and indium 111 oxine have been presented. The diagnosis of osteomyelitis in the lower extremity can often be made on the basis of clinical, laboratory, and conventional radiographic evaluations. In the case report of diabetic osteolysis, initial evaluations revealed osteomyelitis. The use of scanning involving leukocytes labeled with technetium and indium 111 oxine lessened the possibilities of an osseous infection. Studies show the sensitivity, specificity, and accuracy of scans using leukocytes labeled with indium 111 oxine to be superior to those of any other form of nucleotide imaging, but further clinical research is needed.20 references.

  6. Indium-111-labeled leukocyte localization in hematomas: a pitfall in abscess detection

    SciTech Connect

    Wing, V.W.; vanSonnenberg, E.; Kipper, S.; Bieberstein, M.P.

    1984-07-01

    Indium-111-labeled white-blood-cell scanning is a useful modality in abscess detection and has replaced gallium scanning in many institutions. Sensitivities of 72% to 90% and specificities of 90% to 100% have been reported. In searching for abscesses seven cases of indium-111-labeled leukocyte uptake were encountered in collections subsequently proved to be noninfected hematomas. Abundant red blood cells with few or no white blood cells, no bacteria, and a benign clinical course identified these noninfected hematomas. Five of the patients were being treated with hemodialysis and three were recent allograft recipients. The results indicate some limitation and nonspecificity in indium-111 scanning, despite its many benefits.

  7. Noninvasive detection of rejection of transplanted hearts with indium-111-labeled lymphocytes

    SciTech Connect

    Eisen, H.J.; Eisenberg, S.B.; Saffitz, J.E.; Bolman, R.M. 3d.; Sobel, B.E.; Bergmann, S.R.

    1987-04-01

    To determine whether cardiac transplant rejection can be detected noninvasively with indium-111 (/sup 111/In)-labeled lymphocytes, we studied 11 dogs with thoracic heterotopic cardiac transplants without immunosuppression and five dogs with transplants treated with cyclosporine (10 mg/kg/day) and prednisone (1 mg/kg/day). All were evaluated sequentially with gamma scintigraphy after administration of 150 to 350 muCi of autologous /sup 111/In-lymphocytes. Technetium-99m-labeled red blood cells (1 to 3 mCi) were used for correction of radioactivity in the blood pool attributable to circulating labeled lymphocytes. Lymphocyte infiltration was quantified as the ratio of indium in the myocardium of the transplant or native heart compared with that in blood (indium excess, IE). Results were correlated with mechanical and electrical activity of allografts and with histologic findings in sequential biopsy specimens. In untreated dogs (n = 11), IE was 15.5 +/- 7.0 (SD) in transplanted hearts undergoing rejection and 0.4 +/- 1.1 in native hearts on the day before animals were killed. In dogs treated with cyclosporine and prednisone (n = 5), IE was minimal in allografts during the course of immunosuppression (0.8 +/- 0.4) and increased to 22.9 +/- 11.1 after immunosuppression was stopped. Scintigraphic criteria of rejection (IE greater than 2 SD above that in native hearts) correlated with results of biopsies indicative of rejection and appeared before electrophysiologic or mechanical manifestations of dysfunction. Thus infiltration of labeled lymphocytes in allografts, indicative of rejection, is detectable noninvasively by gamma scintigraphy and provides a sensitive approach potentially applicable to clinical monitoring for early detection of rejection and guidance for titration of immunosuppressive measures.

  8. Indium-111 labeled purified granulocytes in the diagnosis of synthetic vascular graft infection

    SciTech Connect

    Forstrom, L.A.; Dewanjee, M.K.; Chowdhury, S.; Brown, M.L.

    1988-12-01

    Indium-111 labeled leukocytes have been shown to be useful in the diagnosis of synthetic vascular graft infection. To minimize the potential effects of labeled red blood cells and platelets on image interpretation, the authors prepared purified autologous granulocytes (PG) from 84 ml of blood using Volex enhanced gravity sedimentation and Ficoll-Hypaque double density centrifugation. The labeling efficiency of PG with In-111 tropolone was 90 +/- 9% (mean +/- SD). Imaging was performed 18-24 hours following injection of approximately 445 microcuries of In-111 PG in 26 patients with suspected infection of vascular grafts that had been implanted 12 days to 12 years prior to the study. In ten patients with proven graft infection, seven had positive In-111 PG scans. Ten of 11 patients without infection had negative scans. In five patients with clinically equivocal findings, scan results were positive in one, negative in one, and equivocal in three. A false-positive scan occurred in a patient with an uninfected inflammatory pseudoaneurysm of an aortic graft. These results confirm an earlier report that In-111 PG imaging is a useful technique in the diagnosis of synthetic vascular graft infection.

  9. Early and delayed indium 111 leukocyte imaging in Crohn's disease

    SciTech Connect

    Navab, F.; Boyd, C.M.; Diner, W.C.; Subramani, R.; Chan, C.

    1987-10-01

    Twenty-seven patients with Crohn's disease were studied for the presence and location of activity by both early (4 h) and delayed (18-24 h) indium 111 leukocyte imaging. The results were compared with other parameters of disease activity including Crohn's disease activity index, barium studies, and endoscopy. There was a correlation between early images and Crohn's disease activity index (r = 0.78) and between delayed images and index (r = 0.82). Based upon the corresponding Crohn's disease activity index, the sensitivity of early and delayed imaging was 81.0% and 95.2%, respectively. Specificity of early and delayed imaging was 75.0% and 87.0%, respectively. Presence of activity on the early and delayed imaging agreed with activity on barium studies and colonoscopy in approximately 80% of cases. Correlation of location of disease by leukocyte imaging and x-ray was observed in 58.9% of early scans and 55.0% of delayed scans. Correlation of the location of disease by imaging and endoscopy was observed in 71.4% of early and 75.0% of delayed studies. Because of the possibility of occurrence of false-negative results in early images, delayed imaging should always be included in evaluation of disease activity in patients with Crohn's disease who are suspected of having mild activity. Delayed imaging is not required if the early imaging study clearly shows activity.

  10. Visualization of a prosthetic vascular graft due to platelet contamination during /sup 111/Indium-labeled leukocyte scintigraphy

    SciTech Connect

    Oates, E.; Ramberg, K.

    1988-09-01

    A prosthetic axillo-femoral bypass graft was visualized during /sup 111/In-labeled leukocyte scintigraphy in a patient referred for possible abdominal abscess. The presence of significant cardiac blood-pool activity raised the possibility that this uptake was due to deposition of contaminating labeled platelets rather than labeled leukocytes. An analysis of a small sample of the patient's blood confirmed that the circulating activity was due to labeled platelets. Increased activity along prosthetic vascular grafts in patients undergoing /sup 111/In-labeled leukocyte scintigraphy may be due to adherent platelet, and not indicative of infection.

  11. Comparison of indium-111 nonspecific polyclonal IgG with indium-111-leukocytes in a canine osteomyelitis model

    SciTech Connect

    Schauwecker, D.S.; Carlson, K.A.; Miller, G.A.; Kalasinski, L.A.; Katz, B.P. )

    1991-07-01

    Osteomyelitis was surgically produced in the proximal tibia of ten dogs. A sham operation was performed on the other tibia. Early (3 hr) and late (20 hr) imaging was performed 1, 4, 7, 10, and 13 wk later, while the osteomyelitis progressed from acute to chronic. Indium-111-IgG had a significantly greater accumulation at the osteomyelitis site than 111In-leukocytes, both during early (p = 0.001) and late (p = 0.03) imaging, and at each of the weeks studied (p less than 0.001). During early imaging, both agents gave equivalent lesion to background ratios. On the late images, the 111In-leukocytes gave significantly higher lesion-to-background ratios than 111In-IgG (p less than 0.001) and higher ratios than they did during the early images (p less than 0.001). Both agents had greater accumulation in acute osteomyelitis than in chronic osteomyelitis (p less than 0.02). Osteomyelitis in the surgical site can be distinguished from the uptake in the sham surgery site using 111In-leukocytes, but not when using 111In-IgG.

  12. Imaging of cardiac allograft rejection in dogs using indium-111 monoclonal antimyosin Fab

    SciTech Connect

    Addonizio, L.J.; Michler, R.E.; Marboe, C.; Esser, P.E.; Johnson, L.L.; Seldin, D.W.; Gersony, W.M.; Alderson, P.O.; Rose, E.A.; Cannon, P.J.

    1987-03-01

    The acute rejection of cardiac allografts is currently diagnosed by the presence of myocyte necrosis on endomyocardial biopsy. We evaluated the efficacy of noninvasive scintigraphic imaging with indium-111-labeled anticardiac myosin Fab fragments (indium-111 antimyosin) to detect and quantify cardiac allograft rejection. Six dogs that had intrathoracic heterotopic cardiac allograft transplantation were injected with indium-111 antimyosin and planar and single photon emission computed tomographic (SPECT) images were obtained in various stages of acute and subacute rejection. Four dogs had an allograft older than 8 months and had been on long-term immunosuppressive therapy; two dogs had an allograft less than 2 weeks old and were not on immunosuppressive therapy. Count ratios comparing heterotopic with native hearts were calculated from both SPECT images and in vitro scans of excised and sectioned hearts and were compared with the degree of rejection scored by an independent histopathologic review. Indium-111 antimyosin uptake was not visible in planar or SPECT images of native hearts. Faint diffuse uptake was apparent in cardiac allografts during long-term immunosuppression and intense radioactivity was present in hearts with electrocardiographic evidence of rejection. The heterotopic to native heart count ratios in SPECT images correlated significantly with the count ratios in the excised hearts (r = 0.93) and with the histopathologic rejection score (r = 0.97). The distribution of indium-111 antimyosin activity in right and left ventricles corresponded to areas of histopathologic abnormalities.

  13. Evaluation of musculoskeletal sepsis with indium-111 white blood cell imaging

    SciTech Connect

    Ouzounian, T.J.; Thompson, L.; Grogan, T.J.; Webber, M.M.; Amstutz, H.C.

    1987-08-01

    The detection of musculoskeletal sepsis, especially following joint replacement, continues to be a challenging problem. Often, even with invasive diagnostic evaluation, the diagnosis of infection remains uncertain. This is a report on the first 55 Indium-111 white blood cell (WBC) images performed in 39 patients for the evaluation of musculoskeletal sepsis. There were 40 negative and 15 positive Indium-111 WBC images. These were correlated with operative culture and tissue pathology, aspiration culture, and clinical findings. Thirty-eight images were performed for the evaluation of possible total joint sepsis (8 positive and 30 negative images); 17 for the evaluation of nonarthroplasty-related musculoskeletal sepsis (7 positive and 10 negative images). Overall, there were 13 true-positive, 39 true-negative, two false-positive, and one false-negative images. Indium-111 WBC imaging is a sensitive and specific means of evaluating musculoskeletal sepsis, especially following total joint replacement.

  14. Pulmonary uptake in Indium-111 leukocyte imaging: clinical significance in patients with suspected occult infections

    SciTech Connect

    Cook, P.S.; Datz, F.L.; Disbro, M.A.; Alazraki, N.P.; Taylor, A.T.

    1984-02-01

    A retrospective review was undertaken to evaluate the frequency and significance of pulmonary activity noted on 306 indium-111 leukocyte studies involving 232 patients with suspected occult infections. Forty-eight studies showed pulmonary activity in one of two patterns of uptake, focal or diffuse. Fourteen of 27 studies (52%) with focal uptake and two of 21 studies (10%) with diffuse uptake were associated with infectious processes. Lung uptake of indium-111-labeled leukocytes was a poor predictor of pulmonary infection in patients studied for occult infection, although the focal pattern was more likely than the diffuse pattern to be associated with infection.

  15. Use of indium-111-labeled white blood cells in the diagnosis of diabetic foot infections

    SciTech Connect

    Zeiger, L.S.; Fox, I.M.

    1990-01-01

    The diagnosis of bone infection in the patient with nonvirgin bone is a diagnostic dilemma. This is especially true in the diabetic patient with a soft tissue infection and an underlying osteoarthropathy. The authors present a retrospective study using the new scintigraphic technique of indium-111-labeled white blood cells as a method of attempting to solve this diagnostic dilemma.

  16. Indium-111 leukocyte imaging in patients with rheumatoid arthritis

    SciTech Connect

    Uno, K.; Matsui, N.; Nohira, K.; Suguro, T.; Kitakata, Y.; Uchiyama, G.; Miyoshi, T.; Uematsu, S.; Inoue, S.; Arimizu, N.

    1986-03-01

    This study evaluates the usefulness of labeled leukocyte imaging in patients with rheumatoid arthritis. In 33 patients, the incidence of pain and swelling in 66 wrist joints and 66 knee joints was compared with the accumulation of (/sup 111/In)leukocytes. No accumulation of (/sup 111/In)leukocytes was seen in any of the patients' wrists (0/12) or knee joints (0/14) when both pain and swelling were absent. In contrast, 93% (25/27) of wrist joints and 80% (24/30) of knee joints with both pain and swelling were positive by (/sup 111/In)leukocyte scintigraphy. There was little correlation between the stage of the disease, as determined by radiography, and (/sup 111/In)leukocyte accumulation. This study suggests that (/sup 111/In)leukocyte imaging may be a reliable procedure for monitoring the activity of rheumatoid arthritis, especially for confirming the lack of an ongoing inflammatory response.

  17. Diagnosis of acute myocardial infarction by indium-111 antimyosin antibodies and correlation with the traditional techniques for the evaluation of extent and localization

    SciTech Connect

    Volpini, M.; Giubbini, R.; Gei, P.; Cuccia, C.; Franzoni, P.; Riva, S.; Terzi, A.; Metra, M.; Bestagno, M.; Visioli, O.

    1989-01-01

    This clinical study evaluated the accuracy of planar myocardial scintigraphy with antimyosin monoclonal antibodies radiolabeled with indium-111 (AMA-Fab) in the detection and localization of acute myocardial infarction (AMI). Fifty-seven patients admitted for suspected AMI were studied; 17 patients underwent thrombolytic therapy with intravenous streptokinase and 11 had clinical signs of reperfusion; 9 had had a previous myocardial infarction. Fifty of 57 patients were discharged from the coronary care unit with a confirmed diagnosis of AMI. The AMA-Fab study results were positive for AMI in 49 patients (98%) and negative in 1 (2%). Among the 7 patients without AMI, 5 had unstable angina, 1 had Prinzmetal's variant angina and 1 had acute pancreatitis. AMA-Fab results were negative in 6 of 7 patients (85%) and positive in 1 (15%). Therefore, the sensitivity and specificity of AMA-Fab scintigraphy were 0.98 and 0.85, respectively. To assess accuracy in defining the extent and location of AMI, AMA-Fab results were compared with those of the electrocardiogram, echocardiogram, technetium-99m pyrophosphate myocardial scintigraphy and coronary angiography and left ventriculography. AMA-Fab scintigraphy showed a good concordance with the traditional techniques in the topographic definition of the infarcted regions. No uptake of AMA-Fab was seen in the regions of previous old infarcts. Ten healthy volunteers also underwent AMA-Fab scintigraphy. No evidence of myocardial tracer uptake was noted in them. No adverse reactions or side effects were noted after injection of AMA-Fab in any patient. It is concluded that planar myocardial scintigraphy with AMA-Fab is a reliable method for AMI detection and location.

  18. Limitations of indium-111 leukocyte scanning in febrile renal transplant patients

    SciTech Connect

    Sebrechts, C.; Biberstein, M.; Klein, J.L.; Witztum, K.F.

    1986-04-01

    Indium-111-labeled leukocyte scanning was evaluated as a technique for investigating possible abscess as the cause of fever in 10 renal allograft recipients under therapy for rejection, acute tubular necrosis, or urinary infection. The usefulness of the method in this setting was found to be limited by marked nonspecificity of renal, pulmonary, and other focal leukocyte accumulation. Although wound infections were correctly identified, false-positive scans resulted in multiple nonproductive consultations and radiologic procedures (some invasive) and contributed to the decision to perform one negative exploratory laparotomy. Such generalized nonspecificity in this patient population is in distinct contrast to the experience with this diagnostic test in nontransplant patients, and has not previously been reported. Possible explanations and implications of these findings are discussed. Consequently, great caution is recommended in the use of indium-111 leukocyte scans to diagnose infection in febrile renal transplant patients who present in a similar clinical setting.

  19. Indium 111-granulocyte scanning in the assessment of disease extent and disease activity in inflammatory bowel disease. A comparison with colonoscopy, histology, and fecal indium 111-granulocyte excretion

    SciTech Connect

    Saverymuttu, S.H.; Camilleri, M.; Rees, H.; Lavender, J.P.; Hodgson, H.J.; Chadwick, V.S.

    1986-05-01

    Indium 111-leukocyte scanning has recently been introduced as a new method for imaging inflammatory bowel disease. The technique has recently been made more specific for acute inflammation by labeling a pure granulocyte fraction rather than the conventional mixed leukocyte preparation. We now report a prospective study comparing 111In-granulocyte scanning with endoscopy, histology, and fecal 111In-granulocyte excretion for the assessment of disease extent and severity in colonic inflammatory bowel disease. In 52 patients with Crohn's disease or ulcerative colitis, disease extent and severity were assessed macroscopically, histologically, or by scanning using a numerical grading system. Excellent correlations were found between both endoscopy and histology and 111In scans (r = 0.90 (endoscopy) and r = 0.90 (histology) for extent; r = 0.86 and r = 0.91 for disease activity). Severity graded by scanning also showed a close correlation with fecal 111In-granulocyte excretion (r = 0.90). Indium 111-granulocyte scans are a rapid, accurate, noninvasive means of assessing both disease extent and severity of colonic involvement in inflammatory bowel disease.

  20. Localization of abscess in adult polycystic kidney by indium-111 leukocyte scan

    SciTech Connect

    Bretan, P.N. Jr.; Price, D.C.; McClure, R.D.

    1988-08-01

    In patients with adult polycystic kidney disease (APKD) infected cysts are difficult to localize with current radiographic techniques, especially those dependent on renal function. Indium-111 leukocyte (In-WBC) imaging is both highly sensitive and effective in detecting and localizing abscesses in patients with renal failure. We report on a patient with APKD and sepsis in whom computed tomography, ultrasound, and physical examination failed to locate the renal abscess, which was found by In-WBC scanning.

  1. Indium-111 white blood cell scans: Sensitivity, specificity, accuracy, and normal patterns of distribution

    SciTech Connect

    Guze, B.H.; Webber, M.M.; Hawkins, R.A.; Sinha, K.

    1990-01-01

    The UCLA Hospital experience with indium-111 labeled white blood cells was reviewed. There were a total of 345 consecutive cases covering a broad range of clinical indications. The overall sensitivity of the method was 79%, specificity was 62%, and accuracy was 73%. The sensitivity for suspected osteomyelitis cases was 84%, with a specificity of 65% and an accuracy of 75%. For other cases sensitivity was 77%, specificity was 60%, and accuracy was 72%. Furthermore, patterns of normal distribution were reviewed.

  2. Indium 111-labeled leukocyte scanning for detection of prosthetic vascular graft infection

    SciTech Connect

    Lawrence, P.F.; Dries, D.J.; Alazraki, N.; Albo, D. Jr.

    1985-01-01

    Recent animal and human studies have suggested that positive indium 111-labeled leukocyte scans may help establish the diagnosis of vascular graft infection; however, there is little information available about the predictive value of both positive and negative leukocyte scans in larger groups of patients. In this study 31 indium 111 leukocyte scans were performed prior to definitive treatment in 21 patients with suspected vascular graft infections. Patients with more than one leukocyte scan performed had either anatomically distinct sites of infection or rescanning of a potentially infected site after definitive treatment. Scans were performed according to the method of Baker et al., attaching 500 muCi of indium 111 to leukocytes with imaging 24 hours later. All patients with positive scans underwent surgical exploration of the area of leukocyte accumulation, with documentation of purulence and culture of the graft. Patients with negative scans were treated as if scan results were indeterminate and underwent surgical exploration for usual clinical indications; if no exploration was performed, the patient was followed up closely for at least 1 year. Twelve of 12 positive scans showed purulence or culture evidence of infection with three different organisms; in 15 instances of negative scans, two operations were performed with one infection noted, whereas no patient without surgery has had a graft infection at 10 months follow-up. In addition to localizing graft infections, two scans demonstrated a nonvascular site of infection. Positive scans also helped determine the extent of infection along the graft, allowing better planning of the surgical procedure. These results indicate that indium 111-labeled leukocyte scans help document and localize prosthetic vascular graft infections.

  3. Comparison of /sup 111/In platelet scintigraphy and two-dimensional echocardiography in the diagnosis of left ventricular thrombi

    SciTech Connect

    Ezekowitz, M.D.; Wilson, D.A.; Smith, E.O.; Burow, R.D.; Harrison, L.H. Jr.; Parker, D.E.; Elkins, R.C.; Peyton, M.; Taylor, F.B.

    1982-06-24

    In a study comparing /sup 111/In platelet scintigraphy and two-dimensional echocardiography as methods of identifying left ventricular thrombi, the results obtained with both techniques were verified at surgery or autopsy in 53 patients--34 with left ventricular aneurysms, and 19 with mitral-valve disease. Left ventricular thrombi were found at surgery or autopsy in 14 of the patients with aneurysms and in none of those with mitral-valve disease. Thirteen of 53 echocardiograms (25 per cent) were technically inadequate and excluded from the analysis. In the group with aneurysms, the sensitivity of scintigraphy in detecting thrombi was 71 per cent, and that of echocardiography was 77 per cent. The specificity of scintigraphy was 100 per cent, and that of echocardiography was 93 per cent. We conclude that /sup 111/In platelet scintigraphy and two-dimensional echocardiography have useful and complementary roles in the detection of left ventricular thrombi. Both these noninvasive techniques can be used to monitor therapy.

  4. Synthesis, biodistribution, and estrogen receptor scintigraphy of indium-111-diethylenetriaminepentaacetic acid-tamoxifen analogue.

    PubMed

    Delpassand, E S; Yang, D J; Wallace, S; Cherif, A; Quadri, S M; Price, J; Joubert, A; Inoue, T; Podoloff, D A

    1996-06-01

    This study was aimed at developing a hydrophilic diethylenetriaminepentaacetic acid-tamoxifen (DTPA-Tam) analogue for use in imaging estrogen receptor positive (ER+) lesions. In rat uterine cytosol, the IC50 of DTPA-Tam conjugate was 1 microM and of tamoxifen, 2 microM. Biodistribution, autoradiography, and radionuclide imaging of 111In-DTPA-Tam in breast-tumor-bearing rats showed that tumor-to-tissue ratios increased steadily between 30 min and 48 h. The in vivo response of MCF-7 breast cancer xenografts to tamoxifen and DTPA-Tam in nude mice demonstrated that DTPA-Tam could reduce tumor growth rate. These results indicate that DTPA-Tam, a new hydrophilic ER+ ligand, might be useful in diagnosing ER+ lesions. PMID:8773948

  5. Clinical uses of radiolabeled platelets

    SciTech Connect

    Datz, F.L.; Christian, P.E.; Baker, W.J.

    1985-12-01

    Platelets were first successfully radiolabeled in 1953. At that time, investigators were primarily interested in developing a technique to accurately measure platelet life span in both normal and thrombocytopenic patients. Studies using platelets labeled with /sup 51/Cr have shown shortened platelet survival times in a number of diseases including idiopathic thrombocytopenic purpura, coronary artery disease, and diabetes mellitus. More recently, labels such as /sup 111/In have been developed that allow in vivo imaging of platelets. Indium-111 platelets are being used to better understand the pathophysiology of atherosclerosis, thrombophlebitis, pulmonary embolism and clotting disorders, and to improve the clinical diagnosis of these diseases.

  6. Clinical application of radiolabelled platelets

    SciTech Connect

    Kessler, C. )

    1990-01-01

    This book presents papers on the clinical applications of radiolabelled platelets. The papers are grouped into six sections on platelet labelling techniques, radiolabelled platelets in cardiology, monitoring of antiplatelet therapy, platelet scintigraphy in stroke patients, platelet scintigraphy in angiology, and platelet scintigraphy in hematology and other clinical applications, including renal transplant rejection.

  7. Noninvasive detection of coronary thrombi with In-111 platelets: concise communication

    SciTech Connect

    Bergmann, S.R.; Lerch, R.A.; Mathias, C.J.; Sobel, B.E.; Welch, M.J.

    1983-02-01

    The need for rapid, definitive identification of coronary thrombosis has been intensified by the advent of thrombolytic therapy and by interest in the role of thrombosis in the etiology of coronary artery disease. To determine whether platelet thrombi can be detected noninvasively with In-111 platelets, a method was developed in which Tc-99m-tagged red blood cells were used to correct for activity within the blood attributable to platelets circulating but not associated with thrombus. In 18 dogs coronary thrombi were induced closed-chest with a copper coil introduced into the coronary artery. Indium-111 platelets and Tc-99m RBCs were administered either before or 1 hr after induction of thrombus, and serial scintigrams obtained. Coronary thrombus was identified readily in the processed scintigrams. In six dogs, thrombolysis was achieved with intracoronary streptokinase. In each case serial scintigraphy demonstrated resolution of the clot. The dual radiotracer technique should permit serial noninvasive delineation of the temporal relationship between platelet deposition and coronary heart disease in patients, and should facilitate the evaluation of interventions designed to prevent platelet aggregation or to lyse existing thrombi.

  8. Ultrasonography and indium 111 white blood cell scanning for the detection of intraabdominal abscesses

    SciTech Connect

    Carroll, B.; Silverman, P.M.; Goodwin, D.A.; McDougall, I.R.

    1981-07-01

    Ultrasound and indium 111 white blood cell scanning were performed on 163 patients with suspected intraabdominal abscesses. In all but one case, intraabdominal abscesses were correctly identified by one or both tests; conversely, no patient was falsely diagnosed by both tests to have an abscess. Sonography was useful in those patients with focal symptoms, and frequently identified nonabscess causes for fever. White cell scanning was valuable when focal signs were absent, and frequently identified extraabdominal sources of sepsis. The two imaging modalities are complementary and provide a highly accurate and sensitive means of intraabdominal abscess detection.

  9. Myocardial Infarct Imaging of Antibodies to Canine Cardiac Myosin with Indium-111-Diethylenetriamine Pentaacetic Acid

    NASA Astrophysics Data System (ADS)

    Khaw, Ban An; Fallon, John T.; Strauss, H. William; Haber, Edgar

    1980-07-01

    Antibodies, by virtue of marked selectivity and affinity, may lend themselves to identification of structures of unique antigenic specificity in vivo. In experimental myocardial infarction in dogs, F(ab')2 fragments of antibodies to cardiac myosin that had been labeled with iodine-131 were shown to localize within the lesion. Because the energy characteristics of iodine isotopes are not ideal for imaging with a gamma camera, a new method for labeling antibody fragments with divalent or polyvalent radionuclides was developed. A bifunctional chelating agent, diethylenetriamine pentaacetic acid was covalently coupled, by an amide bond, to Fab fragments of antibodies to canine cardiac myosin. A stable chelate was then formed with indium-111, a nuclide that has appropriate half-life and energy characteristics for gamma imaging. Antibodies treated in this way retain their antigen-binding activity and are useful in locating myocardial infarcts in vivo.

  10. Indium-111 chloride imaging in patients with suspected abscesses: concise communication

    SciTech Connect

    Sayle, B.A.; Balachandran, S.; Rogers, C.A.

    1983-12-01

    Two hundred and fifty-eight patients with clinically suspected inflammatory processes were studied. Seventy-two images were categorized as true positive; 211 as true negative. There were nine false-positive studies, four of which were due to activity in beds of excised organs. There were six false-negative studies, four of which were due to walled-off abscesses found either at surgery or biopsy. The sensitivity was 92%, the specificity 95%, and the accuracy 94%. This study shows that indium-111 chloride imaging provides a reliable way to locate inflammatory processes and overcomes the disadvantages of other imaging agents, for example gastrointestinal activity or the demonstration of healing surgical wounds with gallium-67, and the false-positive images due to cystic fibrosis and other respiratory diseases, or accessory spleens as seen with In-111-labeled white cells.

  11. Use of indium-111-labeled autologous leukocytes in differentiating pancreatic abscess from pseudocyst

    SciTech Connect

    Bicknell, T.A.; Kohatsu, S.; Goodwin, D.A.

    1981-09-01

    Pancreatic abscess is very difficult to diagnose and the differentiate from pancreatic pseudocyst based on clinical findings, laboratory studies and roentgenographic examinations. Eight patients diagnosed as having a pancreatic mass by ultrasonography or computed tomography also underwent indium-111-labeled autologous leukocyte scanning (10 scans) for suspected intraabdominal sepsis. This scan detects migration of labeled leukocytes into abscesses or areas of inflammation. Four patients had abscess and positive scans, and four patients had pseudocyst and negative scans. There was one false-positive scan in a patient with a recurrent pancreatic mass after drainage of an abscess. Since pancreatic abscess requires prompt drainage, and since it may be preferable to delay drainage of a pseudocyst, the differentiation of these two conditions is important. This test appears very effective in diagnosing pancreatic abscess and differentiating it from a pseudocyst.

  12. Noninvasive detection of human cardiac transplant rejection with indium-111 antimyosin (Fab) imaging

    SciTech Connect

    Frist, W.; Yasuda, T.; Segall, G.; Khaw, B.A.; Strauss, H.W.; Gold, H.; Stinson, E.; Oyer, P.; Baldwin, J.; Billingham, M.

    1987-11-01

    Diagnosis of rejection after cardiac transplantation is currently made by right ventricular endomyocardial biopsy. To evaluate antimyosin imaging as a noninvasive means of detecting human cardiac rejection, the Fab fragment of murine monoclonal antimyosin antibodies was labeled with indium-111 and given intravenously to 18 patients (age 45 +/- 12 years) in 20 studies 7 days to 9 years after transplantation. Endomyocardial biopsy specimens were obtained at the time of each imaging study. Eight patients had positive scans confirmed by biopsy as rejection, and eight patients had negative scans and no evidence of rejection on biopsy. Discordance was observed in four studies, two with positive scans and no rejection on biopsy and two with negative scans and positive biopsy. The sensitivity, specificity, and overall accuracy of the technique were each 80%. Imaging with radiolabeled antimyosin antibody Fab fragments may be of value in the noninvasive identification of rejection in the cardiac transplant recipient.

  13. Myocardial infarct imaging of antibodies to canine cardiac myosin with indium-111-diethylenetriamine pentaacetic acid.

    PubMed

    Khaw, B A; Fallon, F T; Strauss, H W; Haber, E

    1980-07-11

    Antibodies, by virtue of marked selectivity and affinity, may lend themselves to identification of structures of unique antigenic specificity in vivo. In experimental myocardial infarction in dogs, F(ab')2 fragments of antibodies to cardiac myosin that had been labeled with iodine-131 were shown to localize within the lesion. Because the energy characteristics of iodine isotopes are not ideal for imaging with a gamma camera, a new method for labeling antibody fragments with divalent or polyvalent radionuclides was developed. A bifunctional chelating agent, diethylenetriamine pentaacetic acid was covalently coupled, by an amide bond, to Fab fragments of antibodies to canine cardiac myosin. A stable chelate was then formed with indium-111, a nuclide that has appropriate half-life and energy characteristics for gamma imaging. Antibodies treated in this way retain their antigen-binding activity and are useful in locating myocardial infarcts in vivo. PMID:7384803

  14. In-111 labeled leukocyte scintigraphy in a case of multifocal candidiasis

    SciTech Connect

    Palestro, C.J.; Vega, A.; Kim, C.K.; Goldsmith, S.J. )

    1990-06-01

    The value of indium-111 labeled leukocyte scintigraphy for the diagnosis of infection in the general population is well documented; there is less information available on its role in the evaluation of the immunocompromised patient. In this study, leukocyte scintigraphy was performed on a 31-year-old immunocompromised woman who had a possible intra-abdominal abscess. No abscess was detected, but intense oral, esophageal, gastric, and vaginal uptake was observed. Candida infection was histologically confirmed at all four sites.

  15. Platelets

    MedlinePlus

    ... are related to immunity and fighting infection. Platelet Production Platelets are produced in the bone marrow, the ... platelet destruction and also decreased bone marrow platelet production. These problems are caused by autoantibodies. Antibodies are ...

  16. Predictive value of indium-111 antimyosin uptake for improvement of left ventricular wall motion after thrombolysis in acute myocardial infarction

    SciTech Connect

    van Vlies, B.; Baas, J.; Visser, C.A.; van Royen, E.; Delemarre, B.J.; Bot, H.; Dunning, A.J.

    1989-07-15

    In 21 patients treated with thrombolysis for acute myocardial infarction (AMI), the degree of myocardial uptake of indium-111 monoclonal antimyosin antibodies injected within 24 hours after onset of AMI was compared with the degree and extent of regional asynergy on admission and discharge, as assessed by 2-dimensional echocardiography. On the first day of AMI, 80 MBq of indium-111 antimyosin was injected and planar images were made 24 hours later. Indium-111 antimyosin uptake was evaluated for count density index (count density of infarct zone/left lung count density) in the left anterior oblique projection, in which the infarction zone was well displayed in all patients. Using 2-dimensional echocardiography, the left ventricle was divided into 13 segments and evaluated for regional asynergy, which was considered severe (akinesia or dyskinesia) or mild (hypokinesia). The extent of regional asynergy was measured by the number of asynergic segments. All 21 patients had severe regional asynergy on admission. Nine of 21 showed only mild regional asynergy on discharge and 12 of 21 had persistent severe regional asynergy in at least 1 segment. The count density index was significantly lower in patients with mild regional asynergy on discharge compared with patients with severe regional asynergy (1.63 +/- 0.27 vs 2.50 +/- 0.42, p less than 0.01).

  17. Cause and significance of cold bone defects on indium-111-labeled leukocyte imaging

    SciTech Connect

    Datz, F.L.; Thorne, D.A.

    1987-05-01

    Although photon deficient defects on bone scan have received a great deal of interest, such defects in bones on Indium-111 (/sup 111/In) leukocyte imaging have not been as well recognized. We therefore undertook a retrospective review to determine the frequency and significance of such cold defects on /sup 111/In-labeled leukocyte imaging. Three hundred thirty-two scans on 290 patients were reviewed and 40 cases of decreased activity involving bone were found, for an incidence of 12%. The causes of the defects were: fracture (eight), nontraumatic avascular necrosis (eight), solid tumor (six), prostheses and other orthopedic hardware (four), advanced age (four), radiation (three), leukemia (two), osteomyelitis (two), myelofibrosis (one), postlaminectomy (one), and idiopathic (one). To determine the frequency of cold defects in osteomyelitis, all 15 cases of osteomyelitis in this series were reviewed and 12 showed increased activity, two were cold, and one was normoactive. Thus, 14% of cases of osteomyelitis presented as cold defects. We conclude that cold bone defects do occur on /sup 111/In-labeled leukocyte scans and that the causes of such defects are similar to those reported for bone and bone marrow scanning.

  18. Validation of the Monte Carlo simulator GATE for indium-111 imaging.

    PubMed

    Assié, K; Gardin, I; Véra, P; Buvat, I

    2005-07-01

    Monte Carlo simulations are useful for optimizing and assessing single photon emission computed tomography (SPECT) protocols, especially when aiming at measuring quantitative parameters from SPECT images. Before Monte Carlo simulated data can be trusted, the simulation model must be validated. The purpose of this work was to validate the use of GATE, a new Monte Carlo simulation platform based on GEANT4, for modelling indium-111 SPECT data, the quantification of which is of foremost importance for dosimetric studies. To that end, acquisitions of (111)In line sources in air and in water and of a cylindrical phantom were performed, together with the corresponding simulations. The simulation model included Monte Carlo modelling of the camera collimator and of a back-compartment accounting for photomultiplier tubes and associated electronics. Energy spectra, spatial resolution, sensitivity values, images and count profiles obtained for experimental and simulated data were compared. An excellent agreement was found between experimental and simulated energy spectra. For source-to-collimator distances varying from 0 to 20 cm, simulated and experimental spatial resolution differed by less than 2% in air, while the simulated sensitivity values were within 4% of the experimental values. The simulation of the cylindrical phantom closely reproduced the experimental data. These results suggest that GATE enables accurate simulation of (111)In SPECT acquisitions. PMID:15972984

  19. Indium-111 leukocyte scintigraphic detection of myocardial abscess formation in patients with endocarditis

    SciTech Connect

    Cerqueira, M.D.; Jacobson, A.F.

    1989-05-01

    Myocardial abscess formation in patients with bacterial endocarditis in most clinical settings, especially in patients with prosthetic valves, is a primary indicator for surgical valve replacement. We report the detection of myocardial abscesses using /sup 111/In leukocyte scintigraphy in three patients with prosthetic or native valve endocarditis and nondiagnostic echocardiograms. Leukocyte scintigraphy may allow identification of myocardial abscess formation earlier than other imaging modalities.

  20. The value of indium 111 leukocyte scanning in the evaluation of painful or infected total knee arthroplasties

    SciTech Connect

    Rand, J.A.; Brown, M.L. )

    1990-10-01

    Evaluation of painful total knee arthroplasties (TKAs) for infection can be difficult. Indium 111 ({sup 111}In) leukocyte bone scanning provides a minimally invasive technique for evaluation of possible infection. Thirty-eight patients with a painful TKA who had surgical exploration after {sup 111}In leukocyte scanning were reviewed. The scan had an accuracy of 84%, a sensitivity of 83%, and a specificity of 85%. The {sup 111}In leukocyte scans must be interpreted in conjunction with the clinical evaluation of the patient because they are less accurate for study of TKAs than of total hip arthroplasties.

  1. Myocardial uptake of indium-111-labeled antimyosin in acute subendocardial infarction: Clinical, histochemical, and autoradiographic correlation of myocardial necrosis

    SciTech Connect

    Hendel, R.C.; McSherry, B.A.; Leppo, J.A. )

    1990-11-01

    Indium-111-labeled antimyosin has been utilized in the diagnosis and localization of acute transmural myocardial infarction. The present report describes a patient who presented with a massive subendocardial infarction. Two days after the injection of antimyosin, the patient's clinical status markedly deteriorated and he expired. Postmortem examination demonstrated severe three-vessel coronary artery disease with extensive myocyte death in the endocardium. Autoradiography and histochemical staining of the prosected heart demonstrated high correlation for myocardial necrosis and corresponded to clinical evidence for diffuse subendocardial infarction.

  2. Sensitivity of scintigraphy with /sup 111/In-lymphocytes for detection of cardiac allograft rejection

    SciTech Connect

    Eisenberg, S.B.; Eisen, H.J.; Sobel, B.E.; Bergmann, S.R.; Bolman, R.M. 3d.

    1988-12-01

    We recently demonstrated the feasibility of noninvasive detection of cardiac allograft rejection after administration of indium-111-labeled lymphocytes. To determine the sensitivity and specificity of the technique, as well as its value for delineating the severity of rejection, we studied 16 dogs with heterotopic thoracic cardiac allografts. Five animals were evaluated while exposed to immunosuppressive agents. Animals were scanned sequentially after administration of 100-400 microCi of indium-111-labeled autologous lymphocytes. Myocardial lymphocyte infiltration was expressed as the indium excess (IE), defined as the ratio of indium activity of the transplant or native heart compared with that in blood. Scintigraphic results were compared with characteristics of simultaneously obtained endomyocardial biopsies. Among 17 biopsy documented episodes of rejection, 16 were detected scintigraphically. Among 18 biopsies with no evidence of rejection, scintigraphy was uniformly negative. Thus, the sensitivity and specificity of scintigraphy were 94 and 100%, respectively. Biopsies graded as showing no rejection were associated with an IE of 0.3 +/- 0.5 (+/- SD); those graded as mild, 2.8 +/- 1.7; those as moderate, 10.7 +/- 7.2; and those graded as indicative of severe rejection, 14.2 +/- 4.5. Thus, scintigraphy with indium-111-labeled lymphocytes sensitively and specifically detects cardiac allograft rejection and delineates the intensity of the rejection process. It should be useful clinically for assessing potential allograft rejection noninvasively.

  3. Radioimmunoimaging of metastatic medullary carcinoma of the thyroid gland using an indium-111-labeled monoclonal antibody to CEA

    SciTech Connect

    Edington, H.D.; Watson, C.G.; Levine, G.; Tauxe, W.N.; Yousem, S.A.; Unger, M.; Kowal, C.D.

    1988-12-01

    Elevated levels of carcinoembryonic antigen (CEA) or calcitonin after surgical therapy for medullary carcinoma of the thyroid gland (MCT) indicate the presence of residual or metastatic disease. CEA elevations appear to be prognostically more reliable in patients with metastatic disease and suggest a more virulent tumor. Attempts to stage the disease with use of conventional imaging techniques are usually inadequate, as is the therapy for disseminated or recurrent MCT. An indium-111-labeled anti-CEA monoclonal antibody (ZCE-025) was used to image metastases in a patient with MCT. Potential applications of monoclonal antibody technology in the management of MCT would include (1) preoperative differentiation of unicentric from multicentric thyroid gland involvement, (2) detection of regional or distant metastases or both, (3) measurement of response to systemic therapy, and (4) the facilitation of radionuclide immunoconjugate therapy.

  4. Uptake of indium-111-labeled monoclonal antibody ZME-018 as a function of tumor size in a patient with melanoma

    SciTech Connect

    Macey, D.J.; Denardo, S.J.; Denardo, G.L.; Goodnight, J.K.; Unger, M.W.

    1988-01-01

    The accumulation of an Indium-111-labeled monoclonal antibody (MoAb), ZME-018, in melanoma tumors in a patient was determined by sequential, quantitative gamma camera imaging. The amount and concentration of In-111 in each tumor changed in a characteristic pattern with time, reaching a peak at day 3 followed by a steady clearance. The concentration of In-111 in the tumor and the ratios of tumor to whole-body or blood decreased as the size of the tumor increased. These results were interpreted to indicate that the fraction of active, perfused tumor decreased as the melanoma lesions increased in size. The maximum number of MoAb molecules bound per melanoma cell was calculated to be abut 35,000. The implications of these observations for radioimmunoimaging and therapy are significant.

  5. Indium-111-labeled leukocyte scan in detection of synthetic vascular graft infection: The effect of antibiotic treatment

    SciTech Connect

    Chung, C.J.; Hicklin, O.A.; Payan, J.M.; Gordon, L. )

    1991-01-01

    To determine the sensitivity and specificity of the indium-111-({sup 111}In) labeled leukocyte scan for prosthetic vascular graft infection in patients treated with antibiotic therapy, a retrospective study was performed. Of 41 consecutive {sup 111}In-labeled leukocyte scans performed to evaluate possible vascular graft infection, 23 scans were performed in patients treated with antibiotics. The average duration of antibiotic therapy was 21 days. Twelve positive and 11 negative scans for graft infection were found. By surgical and autopsy correlation of all positive cases, and clinical correlation (of all negative cases), there were 10 true-positive, 11 true-negative, 2 false-positive, and no false-negative scans for graft infections, for an overall sensitivity of 100% and specificity of 85%.

  6. Pharmacokinetics of chimeric L6 conjugated to indium-111- and yttrium-90-DOTA-peptide in tumor-bearing mice

    SciTech Connect

    DeNardo, S.J.; Zhong, G.R.; Salako, Q.

    1995-05-01

    A bifunctional chelating agent, DOTA-Gly{sub 3}-L-(p-isothiocyanato)-phenylalanine amide (DOTA-peptide-NCS), was studied in nude mice bearing human breast cancer xenografts (HBT 3477) to determine its potential for radioimmunoconjugate therapy. Indium-111 and yttrium-90 were attached to an anti-adenocarcinoma chimeric L6 (ChL6) monoclonal antibody (MAb) after pre-chelation to the DOTA-peptide-NCS and the desired neutral radiochelates were obtained by purification. The unique characteristic of the DOTA-peptide-NCS to form neutral complexes with trivalent metals was utilized to separate the resulting {sup 111}In and {sup 90}Y radiochelates from excess chelating agent and other anionic by-products resulting from metal impurities. The purified radiochelates were then conjugated to ChL6. The paramacokinetics of {sup 111}In- and {sup 90}Y-DOTA-peptide-ChL6 were obtained for 5 days after injection in nude mice bearing HBT 3477 xenographs. The results were compared with the pharmacokinetics of {sup 125}I-ChL6 obtained in the same mouse model. The whole-body clearance of {sup 125}I-ChL6, {sup 90}Y-and {sup 111}In-DOTA-peptide-ChL6 was monoexponential with biologic half-times of 92, 104 and 160 hr, respectively. Blood clearances of the three radiopharmaceuticals were biphasic. The radiometal immunoconjugates had greater tumor uptake and slower clearances. Indium-111- and {sup 90}Y-DOTA-peptide-ChL6 can be produced at high specific activity with fewer than one chelate per MAb by using a pre-labeling method that permits radiochelate purification by charge selection. Studies in mouse xenografts indicate that tumor uptake in enhanced and a favorable therapeutic index is achieved using these agents. 29 refs., 7 figs., 2 tabs.

  7. Localization of Neuroendocrine Tumors Using Somatostatin Receptor Imaging With Indium-111-Pentetreotide (OctreoScan).

    PubMed

    Ellison; Schirmer; Olsen; Pozderac; Hinkle; Hill; O'Dorisio; O'Dorisio

    1997-01-01

    BACKGROUND: Many imaging methods have been used to detect neuroendocrine tumors of the gastrointestinal system. There is no gold standard for identifying the location of primary tumors and their potential metastases, and most conventional imaging techniques cannot detect tumors less than 1.0 cm in size. METHODS: The authors have investigated the use of 111-In-pentetreotide as an imaging agent for abdominal neuroendocrine tumors. RESULTS: The agent is cleared rapidly by the kidneys and is primarily excreted intact with a biologic half-life of six hours. The largest radiation burden is to the spleen and kidneys. A nine-center study conducted in Europe involved 365 patients with gastroenteropancreatic neuroendocrine tumors that were also imaged by other methods. The results of 111-In-pentetreotide were in agreement with those obtained by other methods for 79% of tumor locations. An additional 110 tumor localizations were detected that were not seen with conventional methods. The smallest gastrinoma imaged by 111-In-pentetreotide was a 4-mm duodenal tumor. CONCLUSIONS: Scintigraphy with 111-In-pentetreotide is effective in visualizing various somatostatin receptors characteristic of neuroendocrine tumors of the gastrointestinal tract. Insulinomas, however, are not well imaged. Concurrent computed tomography scanning is advised to minimize the risk of missing liver metastases. PMID:10763002

  8. Indium-111-antimyosin images compared with triphenyl tetrazolium chloride staining in a patient six days after myocardial infarction

    SciTech Connect

    Jain, D.; Crawley, J.C.; Lahiri, A.; Raftery, E.B. )

    1990-02-01

    The results of indium-111 ({sup 111}In) antimyosin imaging during life and the findings on postmortem imaging and triphenyl tetrazolium chloride (TTC) staining of the heart are reported from a patient who received {sup 111}In-antimyosin on the sixth day following myocardial infarction and died after imaging the next day. The planar images obtained during life showed abnormal {sup 111}In-antimyosin uptake in the posterior, lateral, and apical walls of the left ventricle. Autopsy revealed extensive infarction of the left ventricular lateral and posterior walls with cardiac rupture, which was the cause of sudden death. Direct imaging of the sliced specimen of heart revealed abnormal tracer uptake in the lateral and posterior walls of the left ventricle, which correlated closely with the area of necrosis outlined by TTC staining. Our results confirm the experimental findings that antimyosin antibody binds specifically to the acute irreversibly damaged myocardial cells. A high degree of tracer uptake can be seen even when {sup 111}In-antimyosin is injected six days postinfarction.

  9. Comparison of technetium-99m-HM-PAO leukocytes with indium-111-oxine leukocytes for localizing intraabdominal sepsis

    SciTech Connect

    Mountford, P.J.; Kettle, A.G.; O'Doherty, M.J.; Coakley, A.J. )

    1990-03-01

    Technetium-99m-HM-PAO (({sup 99m}Tc)HM-PAO) leukocyte and indium-111-oxine (111In-oxine) leukocyte scanning were carried out simultaneously in 41 patients at 4 hr and 24 hr after reinjection to determine whether the 4-hr {sup 99m}Tc scan could replace the 24-hr {sup 111}In scan for detecting intraabdominal sepsis. Abdominal infection was confirmed in 12 cases. The 4-hr {sup 99}Tc-leukocyte scan, the 4-hr {sup 111}In-leukocyte scan, and the 24-hr {sup 111}In-leukocyte scan yielded a sensitivity of 100%, 67%, and 100%, respectively, and a specificity of 62%, 90%, and 86%, respectively. The 24-hr {sup 99m}Tc-leukocyte scan also produced a sensitivity of 100%, but it was falsely positive in all 29 cases without infection due to physiologic bowel uptake. False-positive 4-hr {sup 99m}Tc-leukocyte scans were also produced by physiologic bowel uptake in seven cases all of whom had true-negative 4-hr and 24-hr {sup 111}In-leukocyte scans. Because of the high incidence of false-positive 4-hr ({sup 99m}Tc)HM-PAO leukocyte scans, it was concluded that they could not replace 24-hr {sup 111}In-leukocyte scans for detecting intraabdominal sepsis, and that serial {sup 99m}Tc leukocyte scans starting earlier than 4 hr after reinjection must be evaluated.

  10. Scintigraphic assessment of indium-111-labeled granulocyte splenic pooling: A new approach to inflammatory bowel disease activity

    SciTech Connect

    Loreal, O.; Moisan, A.; Bretagne, J.F.; LeCloirec, J.; Raoul, J.L.; Gastard, J.; Herry, J.Y. )

    1990-09-01

    We have conducted a prospective study into the sensitivity and the specificity of the fall in splenic activity (FSA) as an index of activity in inflammatory bowel disease (IBD). FSA was measured on scintiscans obtained at 3 and 24 hr postinjection of indium-111-labeled granulocytes. One hundred and twenty-two scans were acquired in 96 patients who were divided into six groups: Gr. I = normal volunteers (n = 10); Gr. II = inflammatory rheumatism (n = 10); Gr. III = abscesses (n = 17); Gr. IV = ulcerative colitis (UC: n = 23); Gr. V = colonic Crohn's disease (CCD: n = 22); and Gr. VI = ileal Crohn's disease (ICD: n = 14). FSA for Groups I and II was constantly below 10%, but it was increased in the other four groups (abscesses: 39% +/- 12%; UC: 35% +/- 13.5%; CCD: 23.7% +/- 14.7%; ICD: 21.5% +/- 11.7%). There was a significant correlation between fecal excretion of 111In (FEI) and FSA in patients with IBD (UC: r = 0.71, p less than 0.001; CCD: r = 0.74, p less than 0.001; ICD: r = 0.43, p less than 0.001). FSA was followed in 16 patients with IBD after medical treatment and there was a significant correlation between variations in FSA and in FEI (r = 0.879, p less than 0.001). FSA is a very sensitive although nonspecific index of disease activity in IBD and may replace FEI in the assessment of IBD activity.

  11. Indium-111 leukocyte scanning of the abdomen. Analysis of its value for diagnosis and management of inflammatory bowel disease

    SciTech Connect

    Poitras, P.; Carrier, L.; Chartrand, R.; Gagnon, M.; Graveline, R.; Lahaie, R.G.; Martin, F.; Mheir, H.; Picard, D.

    1987-08-01

    Indium-111 leukocyte scanning of the abdomen (IAS) was performed in 10 patients with ulcerative colitis and in 39 patients with Crohn's disease involving the small intestine (in 25 occasions) and/or the colon (17 cases). Radionuclide uptake by the gut was seen in 84% of the patients with active inflammation. We compared the extent of the disease displayed by IAS with the findings obtained by either radiological or endoscopic studies or at surgery. In two-thirds of the patients, the IAS gave an accurate evaluation of the extent of the disease (sensitivity 68%). False-positive IASs were not seen in small bowel disease (specificity 100%), but were observed on 4 occasions on the colon (specificity 86%). The intensity of the radionuclide uptake could not be correlated with the clinical activity of the disease as evaluated by the Crohn's disease activity index. These results suggest that IAS is not superior to the standard procedures used to detect and localize inflammatory bowel disease and that IAS cannot replace these techniques. However, the simplicity of IAS and the complete lack of complications associated with its use render it useful in the evaluation of the extent and distribution of inflammation in some patients, mainly those with severe disease in whom standard diagnostic procedures would be contraindicated.

  12. Radioimmunoimaging of lung vessels: An approach using indium-111-labeled monoclonal antibody to angiotensin-converting enzyme

    SciTech Connect

    Danilov, S.M.; Martynov, A.V.; Klibanov, A.L.; Slinkin, M.A.; Sakharov, I.Yu.; Malov, A.G.; Sergienko, V.B.; Vedernikov, A.Yu.; Muzykantov, V.R.; Torchilin, V.P.

    1989-10-01

    A murine monoclonal antibody against human angiotensin-converting enzyme was radiolabeled with {sup 111}In via diethylenetriaminepentaacetic acid without substantial loss of antigen-binding capacity. This monoclonal antibody designated 9B9 cross-reacted with rat and monkey angiotensin-converting enzyme. Indium-111-labeled 9B9 selectively accumulated 10-20 times greater in the lung than in blood or other organs following intravenous administration in rats. Kinetics of lung accumulation and blood clearance were studied for {sup 111}In-9B9-antibody and compared to that of {sup 125}I-labeled 9B9 in rat. Highly specific accumulation of {sup 111}In-9B9-antibody in the lung of Macaca Rhesus monkeys after intravenous injection was monitored by gamma-imaging. Images of {sup 111}In-labeled antibody 9B9 biodistribution in monkey lung noticeably differ from the images of biodistribution of {sup 99m}Tc-labeled albumin microspheres. This difference may provide information concerning the state of the endothelium of lung capillaries, which is different from the blood flow characteristics determined with routine microsphere technique.

  13. Role of phosphate-containing compounds in the transfer of indium-111 and gallium-67 from transferrin to ferritin.

    PubMed

    Weiner, R E

    1989-01-01

    Physiologic concentrations of ATP stimulate the translocation of gallium-67 (67Ga) from human transferrin (TF) to horse ferritin (HoFE). The mechanism of this translocation was examined. One millimolar ATP did not speed the binding of 67Ga or indium-111 (111In) to HoFE. ATP and pyrophosphate (PPi) at 1 mM, did not form high affinity complexes with 67Ga or 111In. ATP and PPi interacted directly with the [67Ga]TF complex and could within minutes increase the amount of nonprotein-bound 67Ga. Serum HCO3- concentration, 30 mM, prevented the ATP-induced dissociation of 67Ga from TF, whereas intracellular concentrations (0.4 and 5 mM) did not. Using a dialysis technique, ATP also stimulated the translocation of 111In from TF to HoFE; however, this process was much slower than with 67Ga. ATP caused an increase in the nonprotein-bound 111In compared to the control. These results suggest the formation of nonprotein-bound nuclide by these phosphate-containing compounds in a kinetically labile form is important to the translocation mechanism. PMID:2536083

  14. Subacute and chronic bone infections: Diagnosis using In-111, Ga-67 and Tc-99m MDP bone scintigraphy and radiography

    SciTech Connect

    Al-Sheikh, W.; Sfakianakis, G.N.; Mnaymneh, W.; Hourani, M.; Heal, A.; Duncan, R.C.; Burnett, A.; Ashkar, F.S.; Serafini, A.N.

    1985-05-01

    The usefulness of indium-111 white blood cell scintigraphy in the diagnosis of subacute or chronic bone infection was examined in 21 orthopedic patients. In-111 WBC imaging was compared with gallium-67 and technetium-99m methylene diphosphonate skeletal scintigraphy and bone radiography, all studies being performed within 1 week. In-111 WBC scintigraphy showed no definite advantage over Ga-67 scintigraphy in the identification of chronic bone infection. The two tests had the same sensitivity and similar specificity. Bone radiography had a sensitivity of 60% and a specificity of 67%. A negative Tc-99m MDP bone scintigram ruled out infection, but because of low specific, final evaluation required performance of Ga-67 or In-111 WBC scintigraphy.

  15. A comparative study of indium-111 DTPA radionuclide and iothalamate meglumine roentgenographic arthrography in the evaluation of painful total hip arthroplasty

    SciTech Connect

    Maxon, H.R.; Schneider, H.J.; Hopson, C.N.; Miller, E.H.; Von Stein, D.E.; Kereiakes, J.G.; Cummings, D.D.; McDevitt, R.M. )

    1989-08-01

    Fifteen patients with painful total hip prostheses were referred for nuclear medicine and roentgenographic arthrography studies to exclude loosening of the acetabular and/or the femoral component. A new radioisotopic technique suitable for the evaluation of both components was developed using dual-isotope single-photon tomography with {sup 99m}technetium methylene diphosphonate bone imaging and indium-111 diethylenetriaminepentacetic acid arthrography. Thirteen of the 15 subjects were subsequently treated with additional surgery. The surgical findings were compared with the nuclear medicine and roentgenographic results. The overall diagnostic accuracy of both arthrographic procedures was approximately 80%, but the roentgenographic arthrogram was more sensitive and the radionuclide arthrogram was more specific.

  16. Indium-111 leukocyte scintigraphic detection of subclinical osteomyelitis complicating delayed and nonunion long bone fractures: a prospective study

    SciTech Connect

    Esterhai, J.L. Jr.; Goll, S.R.; McCarthy, K.E.; Velchik, M.; Alavi, A.; Brighton, C.T.; Heppenstall, R.B.

    1987-01-01

    Twenty patients were studied prospectively with indium-labeled leukocyte imaging to evaluate its effectiveness in differentiating noninfected delayed or nonunion from osteomyelitis complicating these entities. All patients underwent an open surgical procedure within 24 h of the scan. Bone specimens from the nonunion site were obtained for microbiological and histological analysis to confirm the presence or absence of osteomyelitis. In these twenty patients, the sensitivity of the indium scintigraphy was 100%, the specificity 100%, and the overall accuracy 100%. Indium-labeled leukocyte scintigraphy is significantly more accurate than /sup 99m/technetium and /sup 67/gallium imaging had been, when studied earlier, in detecting subclinical osteomyelitis complicating nonunion. Indium-labeled leukocyte scintigraphy should supplant sequential technetium and gallium studies in this patient population when the surgeon must determine whether subclinical osteomyelitis is complicating fracture management of delayed and nonunions.

  17. Gallium scintigraphy for diagnosis of septic arthritis and osteomyelitis in children

    SciTech Connect

    Borman, T.R.; Johnson, R.A.; Sherman, F.C.

    1986-05-01

    Thirty-four children with presumptive acute osteomyelitis or septic arthritis underwent early gallium-67 citrate scintigraphy and have been retrospectively reviewed. Diagnostic accuracy using this technique was 91%. Gallium-67 citrate is a more reliable radiopharmaceutical agent for the detection of selected acute musculoskeletal infections than either technetium methylene diphosphonate or indium-111. However, the radiation dosage from gallium is higher than from other radiopharmaceutical agents, and the authors would recommend its use only in cases where the diagnosis cannot be made on the basis of clinical, laboratory, or plain roentgenographic criteria.

  18. Intraoperative detection of somatostatin-receptor-positive neuroendocrine tumours using indium-111-labelled DTPA-D-Phe1-octreotide.

    PubMed Central

    Wangberg, B.; Forssell-Aronsson, E.; Tisell, L. E.; Nilsson, O.; Fjalling, M.; Ahlman, H.

    1996-01-01

    After injection of 111In-labelled DTPA-D-Phe1-octreotide, intraoperative tumour localisation was performed using a scintillation detector in 23 patients with neuroendocrine tumours. Count rates from suspect tumour lesions and adjacent normal tissue were expressed as a ratio before (Rin situ) and after (Rex vivo) excision. 111In activity concentration ratios of tumour tissue to blood (T/B) were determined in a gamma counter. In patients with midgut carcinoids, (all scintigraphy positive), false Rin situ recordings were found in 4/29 macroscopically identified tumours. T/B ratios were all high (27-650). In patients with medullary thyroid carcinomas (eight out of ten scintigraphy positive), misleading Rin situ results were found in 4/37 macroscopically identified tumours. T/B ratios were lower (3-39) than those seen in midgut carcinoids. Two out of four patients with endocrine pancreatic tumours had positive scintigraphy, reliable intraoperative measurements and very high T/B ratios (910-1500). One patient with a gastric carcinoid had correct measurements in situ and ex vivo with high T/B ratios (71-210). In situ measurements added little information to preoperative scintigraphy and surgical findings using the present detection system. Rex vivo measurements were more reliable. The very high T/B ratios seen in midgut carcinoids and some endocrine pancreatic tumours would be favourable for future radiation therapy via somatostatin receptors. Images Figure 1 Figure 2 Figure 3 PMID:8611378

  19. Yttrium-90/indium-111 DOTA peptide chimeric L6; pharmacokinetics, dosimetry and initial therapeutic studies in patients with breast cancer

    SciTech Connect

    DeNardo, S.J.; Shen, S.; Richman, C.M.

    1995-05-01

    Chimeric L6 MoAb(ChL6) as I-131 ChL6 has shown therapeutic promise in breast cancer patients. To enhance this potential, we developed yttrium-90 (Y-90) and indium-111 (In-111) ChL6 radiopharmaceuticals by conjugating Y-90 and In-111 DOTA peptide ChL6. Immunoreactivity of In-111 and Y-90 ChL6 was 80-100% of ChL6. Dosimetry was calculated from pharmacokinetics obtained in four studies of patients with metastatic breast cancer using 200 mg ChL6 and 4mCi In-111/3mCi Y-90 DOTA peptide ChL6 in 3 studies and 10 mCi In-111 in one (specific activity 1.1-3.5mCi/mg). Quantitative imaging of In-111 and in vitro analysis of Y-90/In-111 blood and urine clearances and biopsies for bone and marrow uptake were performed. In-111 and Y-90 DOTA peptide ChL6 blood clearances were compared in each patient with {beta} intercepts for each initial study of 13.9/12.7, 4.9/5.8, 25.2/16.2 (%ID), and {beta} T{1/2} 32/30, 33/35, and 41/57 (h) for In- 111/Y-90, respectively. Normal organ and tumor dosimetry for Y-90 DOTA peptide ChL6 was extrapolated from the In-111 kinetics: WB 2.1-2.3, Liver 3.8-5.9, Lung 6.2-7.9, Kidney 8.1-11.3, Spleen 4.4-14.0 (cGy/mCi). Dosimetry of 13 tumored areas (1-10 g) ranged from 42-260 (mean = 103) cGy/mCi. Marrow doses calculated from Y-90 in blood ranged from 0.6-1.5. Marrow biopsies at 5 d pi showed In-111 and Y-90 (%ID/g), 1-2 x 10{sup -3} and 6-7x10{sup -4} and bone 1-3x10{sup -3} and 0.1-3x10{sup -4}, respectively. Compared to our previous I-131 ChL6 dosimetry, this study indicates that the Y-90 DOTA peptide ChL6 radiation dose to tumor is 4-8 times that of I-131 ChL6 whereas normal organs receive less than twice that of I-131 from Y-90. Based on this calculated enhancement of the therapeutic ratio, a multicycle Y-90 DOTA peptide ChL6 therapy protocol has been initiated in breast cancer patients.

  20. Indium-111-labeled leukocyte and technetium-99m-sulfur colloid uptake by a malignant fibrous histiocytoma: phagocytosis by tumor cells?

    PubMed

    Palestro, C J; Klein, M; Kim, C K; Swyer, A J; Goldsmith, S J

    1990-09-01

    Indium-111-labeled leukocyte imaging, performed on a patient with a calcified mass in the right thigh, demonstrated labeled leukocyte accumulation in this mass. Technetium-99m-sulfur colloid imaging was performed to differentiate labeled leukocyte uptake in heterotopic bone marrow from uptake in a focus of infection. Leukocyte and sulfur colloid images were virtually identical, and the study was interpreted as without evidence of infection. Excision of the mass revealed an angiomatoid malignant fibrous histiocytoma with metaplastic bone formation. While no marrow elements were present in either the tumor or the metaplastic bone, phagocytosis of leukocytes by tumor cells was identified. Phagocytosis of leukocytes by tumor cells may be another cause of white cell accumulation in uninfected neoplasms. PMID:2168475

  1. A sensitive new method of ex vivo platelet deposition

    SciTech Connect

    Badimon, L.; Fuster, V.; Dewanjee, M.K.; Romero, J.C.

    1982-10-01

    In 1978, an in vivo quantitative method of platelet aggregation based on the increment of weight of a rabbit tendon when superfused with flowing blood (3 ml/min) derived from a carotid artery of a cat and reentering the contralateral jugular vein was reported. TO increase the sensitivity of the method, researches labeled platelets with indium-111 and reinjected them after two hours; then, with a gamma counter, researches quantitated the /sup 111/In-labeled platelets deposited on the superfused rabbit tendon. Results of the radioactivity method and of the weight method were compared. Researchers found that the /sup 111/In-labeling of platelets was more precise and reproducible method, rendering possible the use of a small amount of blood without need for reentry into the venous system.

  2. Radioisotope labeled platelets in medical diagnosis

    SciTech Connect

    Pope, C.F.; Sostman, H.D.

    1986-08-01

    The myriad of applications of indium-111 labeled platelets (/sup 111/In-P), both in biomedical research and clinical diagnostic imaging, in recent years is an index of the potential of this technology. Because many diseases involve the vascular system, a nontoxic platelet label suitable for imaging has immense potential for diagnosis. Presently confined to research centers, this technique is currently used in three main diagnostic situations: deep vein thrombosis, cardiac thrombi, and organ (renal) transplantation rejection. Future applications will proliferate when difficulties in achieving rapid labeling are overcome, and the period between study initiation and final diagnosis is diminished. This review emphasizes current clinical applications and the potential role of this technology in diagnostic imaging. 52 references.

  3. Platelet thrombosis in cardiac-valve prostheses

    SciTech Connect

    Dewanjee, M.K.

    1989-01-01

    The contribution of platelets and clotting factors in thrombosis on cardiovascular prostheses had been quantified with several tracers. Thrombus formation in vivo could be measured semiquantitatively in animal models and patients with indium-111, Technetium-99m labeled platelets, iodine-123, iodine-131 labeled fibrinogen, and In-111 and Tc-99m labeled antibody to the fibrinogen-receptor on the platelet- membrane, or fibrin. The early studies demonstrated that certain platelet-inhibitors, e.g. sulfinpyrazone, aspirin or aspirin- persantine increased platelet survival time with mechanical valves implanted in the baboon model and patients. Thrombus localization by imaging is possible for large thrombus on thrombogenic surface of prosthesis in the acute phase. The majority of thrombus was found in the sewing ring (Dacron) in the acute phase in both the mechanical and tissue valves. The amount of retained thrombus in both mechanical and tissue valves in our one-day study in the dog model was similar (< 1% if injected In-111 platelets = 5 billion platelets). As the fibrous ingrowth covered the sewing ring, the thrombus formation decreased significantly. Only a small amount of thrombus was found on the leaflets at one month in both the dog and calf models. 38 refs., 9 figs., 5 tabs.

  4. Myocardial distribution of indium-111-antimyosin Fab in acute inferior and right ventricular infarction: comparison with technetium-99m-pyrophosphate imaging and histologic examination

    SciTech Connect

    Nakata, T.; Sakakibara, T.; Noto, T.; Shoji, T.; Tsuda, T.; Kubota, M.; Hattori, A.; Iimura, O. )

    1991-05-01

    In a postmortem study of a 69-yr-old female patient who had suffered 2 yr previously a non-Q-wave anterior infarction and who had sustained just seven days earlier a left inferior and right ventricular infarction, the distribution of {sup 111}In-antimyosin Fab was compared to the results of {sup 99}mTc-pyrophosphate imaging and histologic examination. Indium-111-antimyosin Fab imaging could not be performed because of cardiogenic shock. However, postmortem gamma scintillation counting revealed increased activities of antimyosin Fab in the inferoapical and right ventricular infarcted regions in which {sup 99}mTc-pyrophosphate positive imagings were observed; in contrast, a histologically confirmed old subendocardial anterior infarction had no definite activity. Thus, the myocardial distribution of {sup 111}In-antimyosin Fab corresponded well to the results of {sup 99}mTc scintigrams and histologic examinations in a human heart, suggesting that this technique could be useful in vivo for detecting several-day-old myocardial infarction of the right ventricle as well as the left ventricle. Tissue from the 2-yr-old infarction was not identified by this technique.

  5. Indium-111-leukocyte/technetium-99m-MDP bone and magnetic resonance imaging: Difficulty of diagnosing osteomyelitis in patients with neuropathic osteoarthropathy

    SciTech Connect

    Seabold, J.E.; Flickinger, F.W.; Kao, S.C.; Gleason, T.J.; Kahn, D.; Nepola, J.V.; Marsh, J.L. )

    1990-05-01

    Fourteen patients (16 sites) with clinical and/or radiographic evidence of neuropathic osteoarthropathy (Charcot joints) were evaluated with combined indium-111-leukocyte ({sup 111}In-WBC) and technetium-99m-methylene diphosphonate ({sup 99m}Tc-MDP) bone imaging for suspected osteomyelitis. Magnetic resonance (MR) images were obtained in seven patients. Using a positive bone culture as the criterion for the presence of osteomyelitis, there were four true-positive studies, six true-negative sites, and one false-negative {sup 111}In-WBC study. Five of 16 sites (31%) had false-positive {sup 111}In-WBC uptake at noninfected sites. There were four true-positive and three false-positive MR studies. All false-positives showed at least moderately abnormal findings by both techniques at sites of rapidly progressing osteoarthropathy of recent onset. In this preliminary study, both techniques appear to be sensitive for detection of osteomyelitis, and a negative study makes osteomyelitis unlikely. However, the findings of {sup 111}In-WBC/{sup 99m}Tc-MDP and MR images at sites of rapidly progressing, noninfected neuropathic osteoarthropathy may be indistinguishable from those of osteomyelitis.

  6. Noninvasive radioisotopic technique for detection of platelet deposition in mitral valve prostheses and quantitation of visceral microembolism in dogs

    SciTech Connect

    Dewanjee, M.K.; Fuster, V.; Rao, S.A.; Forshaw, P.L.; Kaye, M.P.

    1983-05-01

    A noninvasive technique has been developed in the dog model for imaging, with a gamma camera, the platelet deposition on Bjoerk-Shiley mitral valve prostheses early postoperatively. At 25 hours after implantation of the prosthesis and 24 hours after intravenous administration of 400 to 500 microCi of platelets labeled with indium-111, the platelet deposition in the sewing ring and perivalvular cardiac tissue can be clearly delineated in a scintiphotograph. An in vitro technique was also developed for quantitation of visceral microemboli in brain, lungs, kidneys, and other tissues. Biodistribution of the labeled platelets was quantitated, and the tissue/blood radioactivity ratio was determined in 22 dogs in four groups: unoperated normal dogs, sham-operated dogs, prosthesis-implanted dogs, and prosthesis-implanted dogs treated with dipyridamole before and aspirin and dipyridamole immediately after operation. Fifteen to 20% of total platelets were consumed as a consequence of the surgical procedure. On quantitation, we found that platelet deposition on the components of the prostheses was significantly reduced in prosthesis-implanted animals treated with dipyridamole and aspirin when compared with prosthesis-implanted, untreated dogs. All prosthesis-implanted animals considered together had a twofold to fourfold increase in tissue/blood radioactivity ratio in comparison with unoperated and sham-operated animals, an indication that the viscera work as filters and trap platelet microemboli that are presumably produced in the region of the mitral valve prostheses. In the dog model, indium-111-labeled platelets thus provide a sensitive marker for noninvasive imaging of platelet deposition on mechanical mitral valve prostheses, in vitro evaluation of platelet microembolism in viscera, in vitro quantitation of surgical consumption of platelets, and evaluation of platelet-inhibitor drugs.

  7. Platelet deposition in rat heart allografts and the effect of a thromboxane receptor antagonist

    SciTech Connect

    Foegh, M.L.; Khirabadi, B.S.; Ramwell, P.W.

    1986-07-01

    The effect of a thromboxane antagonist, L640,035 on platelet deposition in heart allografts was studied. Twenty Lewis rats received heterotopic allografts from Lewis x Brown-Norway F1 hybrid. All recipients received azathioprine (5 mg/kg/day). The rats were divided into three groups. Groups II and III were also treated daily with either the vehicle for L640,035 or L640,035 respectively. Syngeneic indium-111-labeled platelet deposition was determined in the allograft and the native heart at 6, 9, and 13 days after transplantation; group III was studied on the sixth and ninth day only. A rapidly increasing platelet deposition was seen in allografts from rats given azathioprine; whereas the thromboxane antagonist prevented the increase in platelet deposition on the ninth day.

  8. Improved tumor localization with increasing dose of indium-111-labeled anti-carcinoembryonic antigen monoclonal antibody ZCE-025 in metastatic colorectal cancer

    SciTech Connect

    Patt, Y.Z.; Lamki, L.M.; Haynie, T.P.; Unger, M.W.; Rosenblum, M.G.; Shirkhoda, A.; Murray, J.L.

    1988-08-01

    Monoclonal antibodies (MoAbs) against carcinoembryonic antigen (CEA) react with human colorectal cancer cells, and when labeled with a gamma-emitting radioisotope, may help to localize known and occult metastatic disease. We tested ZCE-025, a high-affinity immune gamma globulin1 (IgG1) MoAb anti-CEA that does not react with normal granulocyte glycoproteins in a phase I/II trial to determine the reagent's toxicity and its maximum efficacy in detecting metastatic colorectal cancer. Increasing doses of unlabeled ZCE-025 were mixed with 1 mg of Indium-111 (111In)-radiolabeled MoAb and administered intravenously (IV) to 34 patients who had metastatic colorectal cancer. Planar nuclear or single photon emission computed tomographic (SPECT) scans were performed 48 to 72 and 120 to 144 hours later. Total dose of MoAb and scanning sensitivity (number of imaged lesions/number of known lesions) were correlated up to 80 mg. At doses of 2.5 to 20 mg, a mean of 22% of the lesions were imaged; at 40 mg, 77% were imaged (P less than .01). Liver metastases were detected as areas of increased activity (hot) at the 40 mg dose but showed decreased MoAb uptake at lower doses. At the 40 mg dose normal liver parenchymal uptake of the labeled MoAb was lower with respect to blood pool compared with the other doses. At 80 mg, however, sensitivity of detection declined to 21%. One milligram of 111In-labeled ZCE-025 antibody coinfused with 39 mg of unlabeled antibody appeared optimal for detecting metastatic colorectal cancer, particularly in the liver. Although the exact mechanism(s) for this dose effect is currently unknown, a partial blocking effect of unlabeled antibody with a change in MoAb biodistribution may be occurring.

  9. A Pretherapy Biodistribution and Dosimetry Study of Indium-111-Radiolabeled Trastuzumab in Patients with Human Epidermal Growth Factor Receptor 2-Overexpressing Breast Cancer

    PubMed Central

    Raubitschek, Andrew; Yamauchi, Dave; Williams, Lawrence E.; Wu, Anna M.; Yazaki, Paul; Shively, John E.; Colcher, David; Somlo, George

    2010-01-01

    Abstract Purpose The purposes of this study were to evaluate the organ biodistribution, pharmacokinetics, immunogenicity, and tumor uptake of 111Indium (111In)-MxDTPA-trastuzumab in patients with human epidermal growth factor receptor 2 (HER2)-overexpressing breast cancers and to determine whether 90Y-MxDTPA-trastuzumab should be evaluated in subsequent clinical therapy trials. Experimental Design Patients with HER2-overexpressing breast cancers who were to undergo planned trastuzumab therapy first received unlabeled trastuzumab (4–8 mg/kg IV), followed 4 hours later by 5 mCi 111In-MxDTPA-trastuzumab (10 mg antibody). Serial blood samples, 24-hour urine collections, and nuclear scans were performed at defined time points for 7 days. Results Eight (8) patients received 111In-MxDTPA-trastuzumab, which was well tolerated with no adverse side-effects. Three (3) of 7 patients with known lesions demonstrated positive imaging on nuclear scans. No antiantibody responses were observed for 2 months postinfusion. Organ doses (cGy/mCi) assuming radiolabeling with 90Y were 19.9 for heart wall, 17.6 for liver, 4.6 for red marrow, and 2.8 for the whole body. Tumor doses ranged from 24 to 172 cGy/mCi. Conclusions In summary, results from this study indicate that 90Y-MxDTPA-trastuzumab is an appropriate agent to evaluate in therapy trials. No evidence of an immune response to 111In-MxDTPA-trastuzumab was detected, predicting for the ability to administer multiple cycles. With the exception of cardiac uptake, pharmacokinetics and organ biodistribution were comparable to other 90Y-labeled monoclonal antibodies previously evaluated in the clinic. Cardiac uptake was comparable to hepatic uptake and therefore predicted to not be prohibitively high as to result in dose-limiting cardiotoxicity. PMID:20707718

  10. The systemic activation of platelets by Dacron grafts.

    PubMed

    Shoenfeld, N A; Connolly, R; Ramberg, K; Valeri, C R; Eldrup-Jorgensen, J; Callow, A D

    1988-05-01

    Dacron (polyester fiber), a stimulus to platelet aggregation in vitro, accumulates platelets to a greater extent in vivo than autogenous artery, polytetrafluoroethylene (PTFE) or human umbilical vein (HUV). We conducted a series of experiments using the ex vivo shunt in the baboon to determine whether or not systemic activation of platelet function was produced by a Dacron graft. Two 5 centimeter segments of 4 millimeter internal diameter graft materials were placed in series in the ex vivo shunt perfused at 25 milliliters per minute flow rate for two and one-half hours. Deposition of autologous Indium 111 labeled platelets was monitored. The ex vivo shunt procedures were divided into two groups, both with PTFE as the proximal graft: one with a distal Dacron graft (n = 21), the second with PTFE or HUV distally (n = 17). In this study, an increase in platelet deposition on the proximal PTFE graft represents systemic platelet activation caused by the distal graft. Increased platelet deposition on PTFE was noted at all time points in the presence of a Dacron graft (p less than 0.05). This property of Dacron has important clinical implications, potentially accelerating the progression of vascular disease, increasing the failure rate of composite grafts and subsequent arterial reconstruction. PMID:2966442

  11. Preformed confluent endothelial cell monolayers prevent early platelet deposition on vascular prostheses in baboons

    SciTech Connect

    Schneider, P.A.; Hanson, S.R.; Price, T.M.; Harker, L.A.

    1988-09-01

    We assessed the capacity of preformed confluent endothelial cell (EC) monolayers on small-caliber prosthetic grafts to prevent early platelet deposition in a baboon model. Cultured human umbilical vein ECs were attached to expanded polytetrafluoroethylene (Gore-Tex, 4 mm inner diameter, 3 cm length) precoated with type I collagen and perfused in vitro for 2 hours at 15 ml/min with serum-containing culture medium to achieve cell spreading into confluent monolayers. Cell numbers were quantified by deoxyribonucleic acid assay or isotopic counting of indium 111-labeled ECs. Saturation density for cell attachment was 3.55 +/- 0.29 x 10(5) cells per square centimeter of graft. After 1 hour of in vitro perfusion at 100 ml/min, 92.8% +/- 1.8% of cells remained attached and the flow surface was morphologically confluent. When grafts were inserted as extension segments into arteriovenous silicone rubber (Silastic) shunts in baboons, thereby exposing the endothelialized grafts to native flowing blood (100 ml/min) for 1 hour, the EC monolayers remained confluent with 81.05% +/- 5.88% of the cells attached. Indium 111-labeled platelet deposition onto grafts was quantified by dynamic scintillation camera imaging. Platelet deposition on 10 endothelialized grafts was markedly reduced (0.16 +/- 0.04 x 10(9) platelets per graft) compared with 10 untreated control grafts (1.84 +/- 0.59 x 10(9) platelets, p less than 0.02), eight grafts with early attached unspread ECs (2.38 +/- 0.66 x 10(9) platelets, p less than 0.005), and 11 grafts treated with collagen alone (5.93 +/- 0.72 x 10(9) platelets, p less than 0.002).

  12. Diagnosis of infection by preoperative scintigraphy with indium-labeled white blood cells

    SciTech Connect

    Wukich, D.K.; Abreu, S.H.; Callaghan, J.J.; Van Nostrand, D.; Savory, C.G.; Eggli, D.F.; Garcia, J.E.; Berrey, B.H.

    1987-12-01

    Scintigraphy with indium-labeled white blood cells has been reported to be sensitive and specific in the diagnosis of low-grade sepsis of the musculoskeletal system. We reviewed the records of fifty patients who had suspected osteomyelitis or suspected infection about a total joint prosthesis and who underwent scintigraphy with technetium-99m methylene diphosphonate and scintigraphy with indium-111 oxine-labeled white blood cells before an open surgical procedure. Any patient who received preoperative antibiotics was not included in the study. For all of the patients, gram-stain examination of smears, evaluation of a culture of material from the operative site, and histological examination were done. The patients were divided into two groups. Group I was composed of twenty-four patients, each of whom had a prosthesis in place and complained of pain. Group II was composed of twenty-six patients for whom a diagnosis of chronic osteomyelitis had to be considered. With the indium scans alone, there was only one false-negative result (in Group II), but there were eighteen false-positive results (eight patients in Group II and ten patients in Group I). Although scintigraphy with indium-labeled white blood cells is quite sensitive, it is not specific in detecting chronic osteomyelitis; a negative scan should be considered highly suggestive that osteomyelitis is not present. Specificity can be increased by interpreting the indium scan in conjunction with the technetium scan.

  13. Noninvasive radioisotopic technique for detection of platelet deposition in mitral valve prosthesis and renal microembolism in dogs

    SciTech Connect

    Dewanjee, M.K.; Kaye, M.P.; Fuster, V.; Rao, S.A.

    1980-01-01

    At 24 hrs after implantation of Bjoerk-Shiley mitral prosthesis in 5 dogs, in vivo images were obtained with a gamma camera after intravenous administration (0.5-0.6 mCi) one hour postoperatively of autologous Indium-111-labeled platelets. The site of platelet deposition in the teflon ring and perivascular damaged cardiac tissue is clearly delineated in the scintiphoto. In vitro biodistribution (mean % +/- SD of injected dose) at 24 hrs after injection of the 5 implanted and 7 normal dogs performed with a gamma counter demonstrated that (45.1 +/- 10.6)% and (0.7 +/- 0.4)% were in blood and kidneys in normal dogs and (28.5 +/- 6.8)%, (1.6 +/- 0.6)%, (0.3 +/- 0.1)%, and (0.2 +/- 0.1)% were in blood, kidneys, teflon rings, and perivascular damaged cardiac tissue, respectively. The strut and pyrolytic carbon-coated disc retained only (0.0033 +/- 0.0004)% and (0.0031 +/- 0.0003)%, respectively. There was a 2.3-fold increase of labeled platelets in kidneys of implanted dogs due to renal trapping of microembolism. Also, three- to fivefold increase in ratios of lung, brain, cardiac, and skeletal muscle to blood indicates that internal organs and whole body work as filter for microembolism generated by cardiovascular surgery and mitral prosthesis. Twenty percent of the administered platelets are consumed in surgical repair of damaged tissue. Indium-111-labeled platelets thus provide a sensitive marker for noninvasive imaging of Bjoerk-Shiley mitral prosthesis, thromboembolism after implantation of prosthetic device, and in vitro quantitation of surgical consumption.

  14. 111In platelet imaging of left ventricular thrombi. Predictive value for systemic emboli

    SciTech Connect

    Stratton, J.R.; Ritchie, J.L. )

    1990-04-01

    To determine whether a positive indium 111 platelet image for a left ventricular thrombus, which indicates ongoing thrombogenic activity, predicts an increased risk of systemic embolization, we compared the embolic rate in 34 patients with positive {sup 111}In platelet images with that in 69 patients with negative images during a mean follow-up of 38 +/- 31 (+/- SD) months after platelet imaging. The positive and negative image groups were similar with respect to age (59 +/- 11 vs. 62 +/- 10 years), prevalence of previous infarction (94% vs. 78%, p less than 0.05), time from last infarction (28 +/- 51 vs. 33 +/- 47 months), ejection fraction (29 +/- 14 vs. 33 +/- 14), long-term or paroxysmal atrial fibrillation (15% vs. 26%), warfarin therapy during follow-up (26% vs. 20%), platelet-inhibitory therapy during follow-up (50% vs. 33%), injected {sup 111}In dose (330 +/- 92 vs. 344 +/- 118 microCi), and latest imaging time (greater than or equal to 48 hours in all patients). During follow-up, embolic events occurred in 21% (seven of 34) of patients with positive platelet images for left ventricular thrombi as compared with 3% (two of 69) of patients with negative images (p = 0.002). By actuarial methods, at 42 months after platelet imaging, only 86% of patients with positive images were embolus free as compared with 98% of patients with negative images (p less than 0.01).

  15. Detection of abnormalities in febrile AIDS patients with In-111-labeled leukocyte and Ga-67 scintigraphy

    SciTech Connect

    Fineman, D.S.; Palestro, C.J.; Kim, C.K.; Needle, L.B.; Vallabhajosula, S.; Solomon, R.W.; Goldsmith, S.J.

    1989-03-01

    Thirty-six patients with acquired immunodeficiency syndrome (AIDS), who were febrile but without localizing signs, underwent indium-111 leukocyte scintigraphy 24 hours after injection of labeled white blood cells (WBCs) and were restudied 48 hours after injection of gallium-67 citrate. Fifty-six abnormalities were identified as possible sources of the fever; 27 were confirmed with biopsy. Of these 27, 15 were identified only on In-111 WBC scans (including colitis, sinusitis, and focal bacterial pneumonia); six, only on Ga-67 scans (predominantly Pneumocystis carinii pneumonia and lymphadenopathy); and six, on both studies (predominantly pulmonary lesions). In-111 WBC scanning revealed 21 of 27 abnormalities (78%) and gallium scanning, 12 of 27 (44%). If only one scintigraphic study has been performed, particularly with Ga-67, a significant number of lesions would not have been detected. The authors believe radionuclide evaluation of the febrile AIDS patient without localizing signs should begin with In-111 WBC scintigraphy. Gallium scanning may be used depending on results of In-111 WBC scans or if there is a high index of suspicion for P carinii pneumonia.

  16. Skeletal Scintigraphy

    PubMed Central

    McDougall, I. Ross

    1979-01-01

    Skeletal scintigraphy, using phosphates or diphosphonates labeled with technetium 99m, is a sensitive method of detecting bone abnormalities. The most important and most frequent role of bone scanning is evaluating the skeletal areas in patients who have a primary cancer, especially a malignant condition that has a tendency to spread to bone areas. The bone scan is superior to bone radiographs in diagnosing these abnormalities; 15 percent to 25 percent of patients with breast, prostate or lung cancer, who have normal roentgenograms, also have abnormal scintigrams due to metastases. The majority of bone metastases appear as hot spots on the scan and are easily recognized. The incidence of abnormal bone scans in patients with early stages (I and II) of breast cancer varies from 6 percent to 26 percent, but almost invariably those patients with scan abnormalities have a poor prognosis and should be considered for additional therapies. Progression or regression of bony lesions can be defined through scanning, and abnormal areas can be identified for biopsy. The incidence of metastases in solitary scan lesions in patients with known primary tumors varies from 20 percent to 64 percent. Bone scintigraphy shows positive uptake in 95 percent of cases with acute osteomyelitis. Stress fractures and trauma suspected in battered babies can be diagnosed by scanning before there is radiological evidence. The procedure is free from acute or long-term side effects and, except in cases of very young patients, sedation is seldom necessary. Although the test is sensitive, it is not specific and therefore it is difficult to overemphasize the importance of clinical, radiographic, biochemical and scanning correlation in each patient. ImagesFigure 2.Figure 3.Figure 4.Figure 5.Figure 6.Figure 7.Figure 8.Figure 9.Figure 10. PMID:390886

  17. Accumulation of intimal platelets in cerebral arteries following experimental subarachnoid hemorrhage in cats

    SciTech Connect

    Haining, J.L.; Clower, B.R.; Honma, Y.; Smith, R.R.

    1988-07-01

    From 2 hours to 23 days following experimental subarachnoid hemorrhage, the accumulation of indium-111-labeled platelets on the intimal surface of the middle cerebral artery was studied in 23 cats. Subarachnoid hemorrhage was produced by transorbital rupture of the right middle cerebral artery. Of the 23 cats, 17 exhibited right middle cerebral artery/left middle cerebral artery radioactivity ratios of greater than 1.25. When these results were compared with those of 12 control cats, 0.001 less than p less than 0.005 (chi2 test). Thus, the results from the control and experimental groups are significantly different and indicate early (after 2 hours) preferential accumulation of intimal platelets in the ruptured right middle cerebral artery compared with the unruptured left middle cerebral artery and new platelet deposition continuing for up to 23 days. However, the experimental group did not reveal a clear pattern for platelet accumulation following subarachnoid hemorrhage. There was no simple correlation between the magnitude of the radioactivity ratios and the time after hemorrhage when the cats were killed although the ratios for 2 hours to 7 days seemed greater than those for 8 to 23 days. Assuming the pivotal role of platelets in the angiopathy of subarachnoid hemorrhage, the administration of antiplatelet agents as soon as possible following its occurrence may be of value.

  18. Imaging with indium111-labeled anticarcinoembryonic antigen monoclonal antibody ZCE-025 of recurrent colorectal or carcinoembryonic antigen-producing cancer in patients with rising serum carcinoembryonic antigen levels and occult metastases

    SciTech Connect

    Patt, Y.Z.; Lamki, L.M.; Shanken, J.; Jessup, J.M.; Charnsangavej, C.; Ajani, J.A.; Levin, B.; Merchant, B.; Halverson, C.; Murray, J.L. )

    1990-07-01

    We tested whether nuclear imaging with indium111 (111In)-labeled murine monoclonal (MoAb) anticarcinoembryonic antigen (anti-CEA) ZCE-025 antibody could detect recurrent disease in patients with a rising serum CEA level but negative findings for computed tomographic (CT) scans of the abdomen and pelvis, chest radiograph, and colonoscopy or barium enema. Twenty patients with a history of completely resected CEA-producing adenocarcinoma and a rising serum CEA level were given an intravenous infusion of 2 mg of 111In-labeled ZCE-025 mixed with 38 mg of unlabeled ZCE-025. Planar and single-photon emission CT (SPECT) scans were acquired at 72 and 144 hours, and in 19 of the 20 patients these were positive. Of those 19, 13 underwent exploratory surgery, and cancer was found in 10, and two had a diagnostic biopsy, which confirmed cancer. Three patients who had negative laparotomies and all four patients who did not undergo surgery or biopsy were followed radiologically. In all seven, cancer was subsequently detected at the sites suggested by the ZCE-025 scan. Thus, tumor was confirmed in all 19 patients with positive scans. Five of 13 patients who were explored benefited from the study and the exploratory laparotomy, as disease was entirely resected in four or was subjected to definitive radiation therapy to the pelvis in the fifth. In two additional patients who were not explored, MoAb imaging resulted in definitive therapy to regionally confined recurrent disease. 111In-labeled anti-CEA MoAb ZCE-025 scanning in patients with rising CEA successfully imaged metastatic colorectal cancer that eluded detection by other methods and affected the care given to some. These results suggest an important role for 111In-labeled ZCE-025 scanning among patients with rising CEA and otherwise occult metastatic cancer.

  19. Effect of a selective thromboxane synthase inhibitor on arterial graft patency and platelet deposition in dogs

    SciTech Connect

    McDaniel, M.D.; Huntsman, W.T.; Miett, T.O.; Cronenwett, J.L.

    1987-08-01

    This study examined the effect of selective thromboxane synthase inhibition and nonselective cyclooxygenase inhibition on vascular graft patency and indium 111-labeled platelet deposition in 35 mongrel dogs undergoing carotid artery replacement with 4 mm X 4 cm polytetrafluoroethylene (PTFE) (one side) and Dacron (opposite side) end-to-end grafts. Aspirin-dipyridamole therapy improved one-week graft patency, from 46% in untreated dogs to 93% in treated dogs. Thromboxane synthase inhibition (U-63557A) improved graft patency in these dogs to 81%. Both drug treatments reduced platelet deposition on Dacron and PTFE grafts by 48% to 68% compared with control dogs. Dacron grafts accumulated significantly more platelets than PTFE grafts but had comparable patency rates. Low-dose aspirin therapy had no significant effect on either graft patency or platelet deposition. All treatment groups showed a 60% to 76% reduction in serum thromboxane B2, but only thromboxane synthase inhibitor treatment increased plasma 6-keto-prostaglandin F1 alpha by 100%. Selective thromboxane synthase inhibition improved small-caliber prosthetic graft patency to the same extent as did conventional cyclooxygenase inhibition in this preliminary study.

  20. Discrimination between platelet-mediated and coagulation-mediated mechanisms in a model of complex thrombus formation in vivo

    SciTech Connect

    Cadroy, Y.; Horbett, T.A.; Hanson, S.R.

    1989-04-01

    To study mechanisms of complex thrombus formation in vivo, and to compare the relative antithrombotic effects of anticoagulants and antiplatelet agents, a model was developed in baboons. Segments of collagen-coated tubing followed by two sequentially placed expansion chambers exhibiting disturbed flow patterns were exposed to native blood under laminar flow conditions. The device was incorporated for 1 hour into an exteriorized arteriovenous shunt in baboons under controlled blood flow (20 ml/min). Morphologic evaluation by scanning electron microscopy showed that thrombi associated with collagen were relatively rich in platelets but thrombi in the chambers were rich in fibrin and red cells. Deposition of indium 111-labeled platelets was continuously measured with a scintillation camera. Platelet deposition increased in a linear (collagen-coated segment) or exponential (chambers 1 and 2) fashion over time, with values after 40 minutes averaging 24.1 +/- 3.3 x 10(8) platelets (collagen segment), 16.7 +/- 3.4 x 10(8) platelets (chamber 1), and 8.4 +/- 2.4 x 10(8) platelets (chamber 2). Total fibrinogen deposition after 40 minutes was determined by using iodine 125-labeled baboon fibrinogen and averaged 0.58 +/- 0.14 mg in the collagen segment, 1.51 +/- 0.27 mg in chamber 1, and 0.95 +/- 0.25 mg in chamber 2. Plasma levels of beta-thromboglobulin (beta TG), platelet-factor 4 (PF4), and fibrinopeptide A (FPA) increased fourfold to fivefold after 60 minutes of blood exposure to the thrombotic device. Platelet deposition onto the collagen segment, chamber 1, and chamber 2 was linearly dependent on the circulating platelet count. Platelet accumulation in chamber 1 and chamber 2 was also dependent on the presence of the proximal collagen segment.

  1. Indium-111 autologous leukocyte imaging in pancreatitis

    SciTech Connect

    Anderson, J.R.; Spence, R.A.; Laird, J.D.; Ferguson, W.R.; Kennedy, T.L.

    1986-03-01

    Thirty-nine patients with acute pancreatitis have been assessed using a prognostic factor grading system, abdominal ultrasound, and autologous leukocyte imaging. Both prognostic factor grading and leukocyte imaging can accurately assess the severity of the disease early in its course. All patients with a negative indium-labeled leukocyte image recovered without sequelae, whereas five of the 12 patients with a positive image developed complications, including two deaths. Abdominal ultrasound is of no value in assessing severity, but is a useful method of detecting those patients with gallstone-associated disease. In patients with suspected abscess formation following acute pancreatitis, indium leukocyte imaging does not differentiate between fat necrosis and abscess formation. In this situation, computerized tomography should be carried out before laparotomy is undertaken.

  2. Indium-111 chloride imaging with ununited fractures

    SciTech Connect

    Sayle, B.A.; Fawcett, H.D.; Yudt, W.M.; Wang, S.C.; Mader, J.T.; Cierny, G. 3d.

    1987-03-01

    Twenty patients with ununited fractures and a suspicion of infection had In-111 chloride imaging. Surgically obtained cultures were positive for infection in 12 and negative in eight patients. In-111 chloride images were positive in all 12 patients with infection but also were positive in six of the patients with negative cultures. It is not possible to differentiate infected from noninfected ununited fractures by In-111 chloride imaging.

  3. Influence of endothelial cell seeding on platelet deposition and patency in small-diameter Dacron arterial grafts

    SciTech Connect

    Allen, B.T.; Long, J.A.; Clark, R.E.; Sicard, G.A.; Hopkins, K.T.; Welch, M.J.

    1984-01-01

    Serial platelet deposition, surface topography, and patency were evaluated in control (N . 28) and endothelial cell-seeded (N . 28) small-diameter (4 mm inner diameter) USCI Dacron grafts implanted in the carotid and femoral arteries of dogs. All dogs received aspirin (325 mg) daily for 2 weeks starting 24 hours prior to graft implantation. Endothelial cell seeding was performed by mixing suspensions of autologous endothelial cells that had been enzymatically harvested from segments of external jugular vein with blood that was used to preclot the prostheses. The platelet deposition on each graft was quantitated by means of indium 111-labeled platelets and technetium 99m-labeled red cells in a dual-isotope platelet-imaging technique. Platelet deposition on seeded grafts 24 hours after implantation was significantly higher than on the controls (p less than 0.05). Two weeks after implantation platelet deposition on seeded prostheses had decreased to a level significantly lower than that on the controls and continued to decline on serial studies up to 7 months. In contrast to seeded grafts, platelet accumulation on control grafts dramatically increased after the withdrawal of aspirin therapy and was associated with a sharp rise in control graft thromboses. Cumulative 7-month patency for seeded prostheses was significantly higher than for the controls (96% and 29%, respectively; p less than 0.001). We conclude that endothelial cell seeding in combination with short-term aspirin therapy is a simple, reliable diameter Dacron prostheses. Abrupt withdrawal of aspirin therapy may be contraindicated in nonseeded control grafts because it results in increased platelet deposition and thrombosis.

  4. A perfusion chamber developed to investigate platelet interaction in flowing blood with human vessel wall cells, their extracellular matrix, and purified components.

    PubMed

    Sakariassen, K S; Aarts, P A; de Groot, P G; Houdijk, W P; Sixma, J J

    1983-10-01

    A flat perfusion chamber was developed to study the interaction of blood platelets in flowing blood with cultured human vessel wall cells, their connective tissue matrix, and isolated connective tissue components at defined shear rate conditions. A cover slip covered with endothelial cells or extracellular matrix components was introduced into the chamber. Laser-Doppler velocimetry showed a symmetrical flow profile at flow rates between 50 and 150 ml/min (wall shear rate 300 to 1100 sec-1). Platelet deposition was estimated by using blood platelets labeled with indium-111 or by a morphometric method. Blood platelets did not adhere to endothelial cells at wall shear rates of 765 sec-1 and the endothelial cells remained attached for at least 10 min of perfusion. In preconfluent cultures of endothelial cells, blood platelets adhered to extracellular material in areas between the cells. Removal of endothelial cells by treatment with 0.5% Triton X-100 induced increased platelet adherence with a preference for certain, as yet unidentified, fibrillar structures of the extracellular matrix. Platelet adherence to equine collagen was also studied after coating the cover slips by spraying of small collagen droplets followed by air drying. Platelet adherence and the subsequent platelet aggregate formation occurred predominantly along visible collagen fibers. These studies showed that this perfusion chamber has a laminar and symmetrical flow allowing qualitative and quantitative investigation of platelet interaction with endothelial cells, their extracellular matrix, and pure connective tissue components. A variety of wall shear rates and exposure times can be applied at controlled conditions without removing cells or extracellular material. PMID:6619647

  5. Cardiac and vascular imaging with labeled platelets and leukocytes

    SciTech Connect

    Dewanjee, M.K.

    1984-07-01

    The contribution of platelets in atherosclerosis and thrombosis in animal models and in clinical studies has been quantified with 111In-platelet scintigraphy. New in vitro quantitative techniques have been developed using 111In-labeled platelets to determine the number of adherent platelets on deendothelialized surfaces of damaged vessel walls and synthetic vascular grafts. In vivo imaging techniques are semi-quantitative in nature; in these studies 111In radioactivity on thrombotic vessels or graft surfaces of iliac, femoral, or popliteal arteries is compared with contralateral vessels. Background 111In radioactivity in the circulating blood pool of venous and capillary networks and radioactivity in marrow decreases the sensitivity of these techniques. Subtraction of blood pool radioactivity with 99mTc-labeled autologous red cells and calculation of 111In radioactivity associated with platelet thrombus on vessel walls also have been performed for coronary, carotid, and femoral arteries. Although platelet concentrates are used frequently after open heart surgery (one to six per patient), consumption of platelets in the artificial lung or oxygenator, lysis of platelets during pumping, and suction of blood only recently have been quantified with the use of 111In-labeled platelets. These studies also demonstrated far less trauma to platelets with the use of a membrane rather than a bubble oxygenator. Further reduction in platelet consumption and trauma was observed with the use of prostacyclin, a short-acting drug with significant beneficial effect on platelet thrombus reduction and disaggregation of aggregated platelets. The role of polymorphonuclear leukocytes in inflammation, infection and myocardial infarction, and in vivo evaluation with 111In-leukocyte scintigraphy in animals and humans has been described.

  6. Postoperative bone marrow alterations: Potential pitfalls in the diagnosis of osteomyelitis with In-111-labeled leukocyte scintigraphy

    SciTech Connect

    Seabold, J.E.; Nepola, J.V.; Marsh, J.L.; Hawes, D.R.; Justin, E.P.; Ponto, J.A.; Pettit, W.A.; el-Khoury, G.Y.; Kirchner, P.T. )

    1991-09-01

    Scintigraphy was used after injection of technetium-99m methylene diphosphonate (MDP) and indium-111-labeled white blood cells (WBCs) to assess for the presence of osteomyelitis in 97 patients who had undergone prior surgical procedures. Thirty-four patients with abnormal In-111-labeled WBC patterns underwent restudy with Tc-99m albumin colloid (AC). Scintigraphic findings were considered positive for osteomyelitis whenever localization of In-111-labeled WBCs exceeded Tc-99m AC activity in extent or focal intensity (discordant pattern). Ten of 12 patients with culture-proved osteomyelitis had discordant patterns; two had false-negative (concordant) patterns. The cases of 20 of 22 patients without infection who were considered to have osteomyelitis on the basis of patterns of In-111-labeled WBCs and Tc-99m MDP were reclassified correctly on the basis of concordant patterns of In-111-labeled WBCs and Tc-99m AC. Radiocolloid images improved the overall scintigraphic specificity for osteomyelitis from 59% without bone marrow imaging to 92%; sensitivity decreased from 94% to 88%.

  7. Effects of class I heparin binding growth factor and fibronectin on platelet adhesion and aggregation

    SciTech Connect

    Greisler, H.P.; Klosak, J.J.; Steinam, S.J.; Lam, T.M.; Burgess, W.H.; Kim, D.U. )

    1990-05-01

    Fibronectin and heparin binding growth factor-type 1 have been affixed to vascular graft surfaces to enhance the attachment and the proliferation of transplanted endothelial cells, respectively. The current study examines the effect of fibronectin and heparin binding growth factor-type 1 on platelet adhesion and activation in vivo and on platelet aggregation in vitro. Expanded polytetrafluoroethylene prostheses (5 cm x 4 mm internal diameter) were treated either with fibronectin (n = 9), fibronectin/heparin/heparin binding growth factor-type 1/heparin (n = 12), or neither (n = 13) and were interposed into canine aortoiliac systems bilaterally. Autogenous radiolabeled (Indium 111 oxine, 650 microCi) platelets were injected intravenously before reestablishment of circulation. Perfusion was maintained for 30 minutes, and prostheses were removed with segments of native aorta and distal iliac arteries bilaterally. Specimens were examined for thrombus-free surface area, by gamma well counting for adherent radiolabeled platelets, and by light microscopy and transmission and scanning electron microscopic techniques. Results showed that both the fibronectin and fibronectin/heparin/heparin binding growth factor-type 1/heparin pretreated prostheses contained significantly greater numbers of platelets and adherent radioactivity than did control graft segments when normalized to their ipsilateral iliac arteries. Fibronectin/heparin/heparin binding growth factor-type 1/heparin pretreated prostheses contained 27 +/- 16 times more radioactivity per square millimeter than ipsilateral iliac arteries, fibronectin pretreated prostheses had 13 +/- 8 times more radioactivity per square millimeter than ipsilateral iliac arteries, and untreated expanded polytetrafluoroethylene had 4 +/- 3 times more radioactivity per square millimeter than ipsilateral iliac arteries.

  8. PLATELET FORMATION

    PubMed Central

    Thon, Jonathan N.; Italiano, Joseph E.

    2010-01-01

    Thrombocytopenia is the underlying cause of a number of major clinical conditions and genetic disorders worldwide. While therapeutic agents that bind and stimulate the thrombopoietin receptor are currently available, the development of drugs that directly stimulate megakaryocytes to generate platelets has lagged behind. To improve the management of thrombocytopenia, we will need to define the cell biological pathways that drive the production of platelets from megakaryocytes. This review integrates the latest research of platelet biogenesis and focuses on the molecular pathways that power and regulate proplatelet production. PMID:20620432

  9. Platelet count

    MedlinePlus

    ... reactions Cancer Certain medicines Bone marrow disease called polycythemia vera Bone marrow making too many platelets without a ... leukemia (CML) Hemolytic anemia Idiopathic thrombocytopenic purpura (ITP) Polycythemia vera Thrombocytopenia Patient Instructions Deep vein thrombosis - discharge Update ...

  10. Platelet Count

    MedlinePlus

    ... rash Small purplish spots on the skin called purpura, caused by bleeding under the skin Testing may ... Idiopathic thrombocytopenia (ITP), also known as immune thrombocytopenic purpura, is the result of antibody production against platelets. ...

  11. Extraction, radiolabeling, and in vivo catabolism of autologous-origin equine fibrinogen and platelets in the healthy and exercise-stressed horse

    SciTech Connect

    Coyne, C.P.

    1986-01-01

    Three separate techniques were evaluated for the extraction of autologous-origin fibrinogen from whole equine plasma. Rapid extraction of equine fibrinogen with ammonium sulfate-sodium phosphate buffer, in combination with saturated glycine buffer, provided the most practical means of obtaining a protein extract with the highest degree of biological activity and sufficiently high iodine-125 (/sup 125/I) radiolabeling efficiencies using monochloroiodine reagent (ICI). A technique was developed for the in vitro radiolabeling of equine platelets suspended in plasma. This entailed the use of the isotope, indium-111 (/sup 111/In), together with the lipophilic ligand, 2-(mercaptopyridine-N-oxide). This labeling technique achieved labeling efficiencies between 75% and 96%, and in vitro aggregability of /sup 111/In-merc radiolabeled platelets was comparable to that of unlabeled cell isolates. In the final phase of the investigation, autologous-origin /sup 125/I-labeled fibrinogen and /sup 111/In-labeled platelets were applied in a series of equine exercise physiology studies. Elimination of these two radiobiologicals was evaluated in the resting and exercise-stressed horse. Results from these investigations revealed no long-term influence of exercise conditioning on the in vivo kinetics of radiolabeled fibrinogen or platelets.

  12. Platelet aggregation test

    MedlinePlus

    The platelet aggregation blood test checks how well platelets , a part of blood, clump together and cause blood to clot. ... Decreased platelet aggregation may be due to: Autoimmune ... Fibrin degradation products Inherited platelet function defects ...

  13. sup 111 Indium-labeled neutrophil migration into the lungs of bleomycin-treated rabbits assessed noninvasively by external scintigraphy

    SciTech Connect

    Haslett, C.; Shen, A.S.; Feldsien, D.C.; Allen, D.; Henson, P.M.; Cherniack, R.M. )

    1989-09-01

    Factors controlling neutrophil migration into the lung are poorly understood, but their identification is important for our understanding of the pathogenesis of inflammatory lung diseases. Pulmonary inflammation is difficult to quantify, and neutrophils in tissues and BAL may not accurately represent cell migration. In this study, intravenously delivered pulses of rabbit neutrophils labeled with Indium-111 (111In-neutrophils) were used to monitor neutrophil migration into the lungs. Radioactivity quantified in the lung region of interest (ROI) of external gamma camera scintigrams recorded 24 h after intravenous 111In-neutrophil injection accurately reflected the actual neutrophil-associated lung tissue radioactivity. ROI radioactivity at 24 h also correlated closely with the percent of 111In-neutrophils that had migrated into lavageable air spaces, and this parameter therefore provided an index of total lung 111In-neutrophil migration. Using 24-h ROI radioactivity and percent of injected 111In-neutrophils recovered in BAL at 24 h as indices of neutrophil migration into the lung, it was found that intratracheal saline caused only a transient neutrophil migration, whereas 10 U/kg intratracheal bleomycin induced migration that persisted for as long as 3 wk. 111In-neutrophil migration into the lung, assessed by external scintigraphy, correlated with total neutrophils quantified in histologic sections (r = 0.71, p = 0.006). The data suggest that this approach will be valuable in investigating mechanisms controlling neutrophil migration in lung inflammation, and that 111In-neutrophil scintigraphy may provide a noninvasive index of total lung neutrophil load that might be useful in staging inflammation in patchy diseases such as idiopathic pulmonary fibrosis.

  14. Clinical comparison of indium-111 acetylacetone and indium-111 tropolone granulocytes

    SciTech Connect

    Schauwecker, D.S.; Burt, R.W.; Park, H.M.; Mock, B.H.; Witt, R.M.; Tobolski, M.M.; Wellman, H.N.

    1986-11-01

    This clinical study compares the efficacy of two /sup 111/In white blood cells preparations. Seventy-six patients were imaged after an injection of granulocytes (GRAN) isolated on a Ficoll-Hypaque gradient and labeled with (/sup 111/In)acetylacetone (ACAC) in saline; 105 patients were imaged after an injection of GRAN isolated on a metrizamide-plasma gradient and labeled with (/sup 111/In)tropolone (TROP) in plasma. Early (2-4 hr), intermediate (4-6 hr), and delayed (24 hr) images were obtained. The specificity was quite high (94-100%) in both preparations and no statistical differences could be found. The sensitivity for ACAC-GRAN for the early, intermediate, and delayed images were 39%, 63%, and 64%, respectively; for TROP-GRAN it was 80%, 89%, and 92%, respectively. In all cases the TROP-GRAN images were significantly more sensitive than the ACAC-GRAN images obtained at the same time after injection (p less than 0.001 for early and delayed images, 0.01 less than p less than 0.025 for intermediate images). For ACAC-GRAN the intermediate and delayed images were significantly more sensitive than the early images, while no significant difference could be found for TROP-GRAN. In a blinded experiment, the ability of TROP-GRAN to demonstrate a lesion was compared to that of ACAC-GRAN. TROP-GRAN demonstrated the lesions better than ACAC-GRAN, both in the early and late images (p less than 0.001). TROP-GRAN visualization scores at 4-6 hr equaled those obtained 24 hr after injection. In conclusion, GRAN separated and labeled in plasma with TROP are superior to those separated and labeled in saline with ACAC in three ways: higher visualization scores, earlier visualization of the lesion, and greater sensitivity.

  15. Viability and functional integrity of washed platelets.

    PubMed

    Pineda, A A; Zylstra, V W; Clare, D E; Dewanjee, M K; Forstrom, L A

    1989-01-01

    The viability and functional integrity of saline- and ACD-saline-washed platelets were compared with those of unwashed platelets. After template bleeding time (TBT) was measured, 15 healthy volunteers underwent plateletpheresis and ingested 600 mg of aspirin. Autologous 111In-labeled platelets were transfused: unwashed (n = 5), washed with 0.9 percent saline solution (SS) (n = 5), and washed with a buffered 12.6 percent solution of ACD-A in 0.9 percent saline solution (n = 5). After transfusion, we measured TBT at 1, 4, and 24 hours; platelet survival at 10 minutes and 1, 4, and 24 hours and daily for 6 days; and the percentage of uptake in liver and spleen by quantitative whole-body radionuclide scintigraphy at 24 and 190 hours. We found that saline washing affected platelet recovery, 23.47 +/- 12 percent (p less than 0.001) as compared to 52.43 +/- 17 percent (p less than 0.002) for ACD-saline and 73.17 +/- 8 percent for control; that saline washing resulted in a greater liver uptake than control and ACD-saline-washed platelets (31.9 +/- 8% [p less than 0.001] vs 17.7 +/- 4.1 and 19.3 +/- 2.1% [p greater than 0.1], respectively); that, unlike control and ACD-saline-washed platelets, saline-washed platelets did not shorten bleeding time; and that neither type of washing affected survival. Although ACD-saline washing affects recovery, it also results in intact function, normal survival, higher recovery than SS platelets, and no significant liver uptake. PMID:2749876

  16. Viability and functional integrity of washed platelets

    SciTech Connect

    Pineda, A.A.; Zylstra, V.W.; Clare, D.E.; Dewanjee, M.K.; Forstrom, L.A.

    1989-07-01

    The viability and functional integrity of saline- and ACD-saline-washed platelets were compared with those of unwashed platelets. After template bleeding time (TBT) was measured, 15 healthy volunteers underwent plateletpheresis and ingested 600 mg of aspirin. Autologous /sup 111/In-labeled platelets were transfused: unwashed (n = 5), washed with 0.9 percent saline solution (SS) (n = 5), and washed with a buffered 12.6 percent solution of ACD-A in 0.9 percent saline solution (n = 5). After transfusion, we measured TBT at 1, 4, and 24 hours; platelet survival at 10 minutes and 1, 4, and 24 hours and daily for 6 days; and the percentage of uptake in liver and spleen by quantitative whole-body radionuclide scintigraphy at 24 and 190 hours. We found that saline washing affected platelet recovery, 23.47 +/- 12 percent (p less than 0.001) as compared to 52.43 +/- 17 percent (p less than 0.002) for ACD-saline and 73.17 +/- 8 percent for control; that saline washing resulted in a greater liver uptake than control and ACD-saline-washed platelets (31.9 +/- 8% (p less than 0.001) vs 17.7 +/- 4.1 and 19.3 +/- 2.1% (p greater than 0.1), respectively); that, unlike control and ACD-saline-washed platelets, saline-washed platelets did not shorten bleeding time; and that neither type of washing affected survival. Although ACD-saline washing affects recovery, it also results in intact function, normal survival, higher recovery than SS platelets, and no significant liver uptake.

  17. Gastrointestinal transit of a solid indigestible capsule as measured by radiotelemetry and dual gamma scintigraphy

    SciTech Connect

    Mojaverian, P.; Chan, K.; Desai, A.; John, V. )

    1989-08-01

    The objectives of the present study were to evaluate gastric and small bowel transit times of an indigestible solid matrix and to characterize the specific changes in intraluminal pH as a function of transit time through the gastrointestinal tract. Particular attention was paid to the lag time at the ileocecal junction. A Heidelberg capsule (HC), labeled with 10 microCi Indium-111, was given orally to six healthy male subjects 15 min after oral ingestion of 100 microCi of 99mTc-sulfur colloid as a liquid fatty meal (4 ml/kg). Intraluminal pH was monitored continuously via the HC. Gastric and small bowel transit of the radionuclides was monitored via external scintigraphy at 0.5-hr intervals. Gastric residence times (GRT) of the HC ranged from 2.8 to 4.8 hr. with a mean (+/- SD) of 3.6 +/- 0.8 hr. These values were independent of the individual's weight, height, or body surface area. Small bowel transit times of the HC ranged from 2.8 to greater than 5.5 hr. which were consistent with the reported values of 3 to 5 hr. The lag times of the HC at ileocecal junction ranged from 0.8 to greater than 2.5 hr. The presence of the lag times at the ileocecal junction in all subjects confirmed that it acts as a valve or sphincter. Mouth-to-cecum transit times of the HC occurred within 9.0 hr in 50% of the subjects. In general, following a sharp rise upon pyloric passage of HC the pH dropped slightly but then increased linearly throughout the small intestine.

  18. Platelet kinetics and scintigraphic imaging in thrombocytopenic malaria patients.

    PubMed

    Karanikas, Georgios; Zedwitz-Liebenstein, Konstantin; Eidherr, Harald; Schuetz, Matthias; Sauerman, Robert; Dudczak, Robert; Winkler, Stefan; Pabinger, Ingrid; Kletter, Kurt

    2004-03-01

    Thrombocytopenia is a common occurrence in acute malaria. It is attributed, among other factors, to excessive splenic platelet pooling and a shortened platelet lifespan. The aim of our study was to evaluate the platelet kinetics and sequestration site by isotopic studies in uncomplicated malaria-induced thrombocytopenia. Seven thrombocytopenic malaria patients (74,000+/-36,000 platelets/ micro l) were included in the study. Autologous (111)In-labeled platelet scintigraphy was performed up to 96 hours (h) post injection (p.i.) to evaluate the platelet sequestration site. Late sequestration for the spleen (S) and the liver (L) was analyzed according to the following activity ratios: S (spleen count on the last day of the platelet lifespan / spleen count at 30 min) and L (liver count on the last day of the platelet lifespan / liver count at 30 min). Additionally, platelet survival studies were performed. A normal late sequestration (S: 0.95+/-0.06 and L: 1.04+/-0.08; normal values, S and L: 1+/-0.2.) was observed in all of our patients. The platelet lifespan was reduced (1 to 4 days; normal range, 7-9 days), recovery was normal (mean, 63+/-6%; normal range, 55-75%), and the turnover rate was enhanced (mean, 95,000+/-80,000/ micro l/day; normal value, 35,000+/-4,500/ micro l/ day). According to the results of scintigraphy, the sequestration site by uncomplicated malaria-induced thrombocytopenia appears to be non-splenic and/or hepatic, yet diffuse. PMID:14983232

  19. Platelet aggregation test

    MedlinePlus

    ... this page: //medlineplus.gov/ency/article/003669.htm Platelet aggregation test To use the sharing features on this page, please enable JavaScript. The platelet aggregation blood test checks how well platelets , a ...

  20. Hepatobiliary scintigraphy in children.

    PubMed

    Nadel, H R

    1996-01-01

    Hepatobiliary scintigraphy using iminodiacetic (IDA) radiopharmaceuticals provides clinically useful information on the function of the biliary tract in a variety of pathological processes in children, including neonatal jaundice, gallbladder dysfunction, trauma, and liver transplantation. Phenobarbital premedication (5 mg/kg per day for a minimum of 5 days in divided doses) is used in infants who are being examined for neonatal jaundice to increase the accuracy of 99mTc-IDA scintigraphy in differentiating extrahepatic biliary atresia from neonatal hepatitis. Biliary atresia can be ruled out in an infant if a patent biliary tree is shown with passage of activity into the bowel. If no radiopharmaceutical is noted in the bowel on imaging up to 24 hours, distinction between severe hepatocellular disease and biliary atresia cannot be made. The literature reports 91% accuracy, 97% sensitivity, and 82% specificity for hepatobiliary imaging in the diagnosis of biliary atresia. The impairment of both intrahepatic and extrahepatic biliary drainage is an important cause of liver disease in cystic fibrosis. Hepatobiliary scintigraphy in cystic fibrosis has shown characteristic patterns of dilatation of mainly the left hepatic duct, narrowing of the distal common bile duct, gallbladder dysfunction, and delayed bowel transit. Cholecystitis in children may be acalculous. Sensitivity and specificity for the scintigraphic diagnosis of acute acalculous cholecystitis is reported to range from 68% to 93% and 38% to 93%, respectively. Cholescintigraphy in a suspected bile leak provides information generally not available with other techniques, except for direct cholangiography. If the amount of intraperitoneal accumulation of the tracer is greater than that entering the gastrointestinal tract, surgery is usually indicated. Hepatobiliary imaging in children who have undergone liver transplantation will assess graft vascularity, parenchymal function, biliary drainage, presence of a leak

  1. Activated Platelets in Carotid Artery Thrombosis in Mice Can Be Selectively Targeted with a Radiolabeled Single-Chain Antibody

    PubMed Central

    Goldschmidt, Jürgen; Pethe, Annette; Hagemeyer, Christoph E.; Neudorfer, Irene; Zirlik, Andreas; Weber, Wolfgang A.; Bode, Christoph; Meyer, Philipp T.

    2011-01-01

    Background Activated platelets can be found on the surface of inflamed, rupture-prone and ruptured plaques as well as in intravascular thrombosis. They are key players in thrombosis and atherosclerosis. In this study we describe the construction of a radiolabeled single-chain antibody targeting the LIBS-epitope of activated platelets to selectively depict platelet activation and wall-adherent non-occlusive thrombosis in a mouse model with nuclear imaging using in vitro and ex vivo autoradiography as well as small animal SPECT-CT for in vivo analysis. Methodology/Principal Findings LIBS as well as an unspecific control single-chain antibody were labeled with 111Indium (111In) via bifunctional DTPA ( = 111In-LIBS/111In-control). Autoradiography after incubation with 111In-LIBS on activated platelets in vitro (mean 3866±28 DLU/mm2, 4010±630 DLU/mm2 and 4520±293 DLU/mm2) produced a significantly higher ligand uptake compared to 111In-control (2101±76 DLU/mm2, 1181±96 DLU/mm2 and 1866±246 DLU/mm2) indicating a specific binding to activated platelets; P<0.05. Applying these findings to an ex vivo mouse model of carotid artery thrombosis revealed a significant increase in ligand uptake after injection of 111In-LIBS in the presence of small thrombi compared to the non-injured side, as confirmed by histology (49630±10650 DLU/mm2 vs. 17390±7470 DLU/mm2; P<0.05). These findings could also be reproduced in vivo. SPECT-CT analysis of the injured carotid artery with 111In-LIBS resulted in a significant increase of the target-to-background ratio compared to 111In-control (1.99±0.36 vs. 1.1±0.24; P<0.01). Conclusions/Significance Nuclear imaging with 111In-LIBS allows the detection of platelet activation in vitro and ex vivo with high sensitivity. Using SPECT-CT, wall-adherent activated platelets in carotid arteries could be depicted in vivo. These results encourage further studies elucidating the role of activated platelets in plaque pathology and atherosclerosis

  2. Estrogen receptor scintigraphy.

    PubMed

    Scheidhauer, K; Scharl, A; Schicha, H

    1998-03-01

    Radio-labeled estrogen receptor ligands are tracers that can be used for functional receptor diagnosis. Their specificity towards receptors, together with the fact that only 50-70% of mammary carcinomas are receptor positive, renders them unsuitable for detection of primary tumors or metastases, and this means that estrogen receptor scintigraphy can be used neither for tumor screening nor for staging. However, both 18F-labeled and 123I-labeled estradiol derivatives are suitable for in vivo imaging of estrogen receptors. Their high specificity, established in animal experiments and in vitro studies has been reproduced in in vivo applications in humans. Tracers with positron radiation emitters are, however, hardly suitable for broad application owing to the short half-life of 18F, which would mean that users would need to be situated close to a cyclotron and a correspondingly equipped radiochemical laboratory. The number of available PET scanners, on the other hand, has increased over the last few years, especially in Germany, so that this, at least, does not present a limiting factor. All the same, 123I-labeled estradiol derivatives will find more widespread application, since the number of gamma-cameras incorporating modern multi-head systems is several times greater. The results of studies with 123I-E2-scintigraphy published to date are very promising, even given the initial technical problems mentioned above. As a method of examination, it could be optimised by using improved tracers with a higher tumor contrast and less disturbance from overlapping in diagnostically relevant locations, for instance, by selecting tracers with higher activities whose excretion is more renal than hepatobiliary. The use of modern multi-head camera systems can also be expected to improve the photon yield. PMID:9646642

  3. Acquired platelet function defect

    MedlinePlus

    ... dark black, or tarry bowel movements ; or vomiting blood or material that looks like coffee grounds Nosebleeds ... Tests that may done include: Bleeding time Platelet aggregation test Platelet count PT and PTT

  4. Congenital platelet function defects

    MedlinePlus

    Kottke-Marchant K. Platelet disorders. In: Hsi ED, ed. Hematopathology . 2nd ed. Philadelphia, PA: Elsevier Saunders; 2012:chap 2. Nichols WL. Von Willebrand disease and hemorrhagic abnormalities of platelet ...

  5. Interest of somatostatin receptors scintigraphy for imaging differentiated thyroid carcinoma tumor sites

    SciTech Connect

    Giammarile, F.; Lumbroso, J.; Schlumberger, M.

    1995-05-01

    Despite the fact that differentiated thyroid carcinoma (DTC) is not classified as a neuroendocrine tumor, there is an increasing interest for the use of somatostatin receptors scintigraphy (SRS) in this disease. We evaluated SRS in DTC patients having no or a poor radioiodine uptake at the level of their tumor sites. Nine patients (pts) (7 men, 2 women; aged from 52 to 65 years) were previously treated (surgery of the primary: 9/9pts; followed by cervical radiotherapy: 4/9pts; radioiodine therapy: 8/9pts; surgery or radiotherapy to bone metastases: 2/9 pts) for DTC (papillary form: 6 pts; follicular; 1 pts; insular: 2 pts). They were explored by conventional imaging modalities (CIM) including Tc-99m MDP bone scans. High activity radioiodine scans were obtained 5 days after I-131 therapy. SRS was carried out during thyroxine therapy using Indium-111 pentetreotide (120 MBq) with imaging at 4 and 24 hours after injection (whole body scans and, when necessary, SPECT). Thyroglobulin blood level ranged from 120 to 60,000ng/ml. SRS was positive at the level of all tumor sites in 8/9 pts; radioiodine scans were negative in 4 pts (1pt with an insular DTC, 3 pt with a papillary DTC), slightly positive in 2 pts (papillary DTC), positive only on part of tumor sites in 1 pts (insular DTC), positive in 1 pt (follicular DTC) and not done in 1 pt. SRS demonstrated 3 new tumor sites (1 to bone, 1 to lung and 1 to mediastinal lymph nodes) in 2 pts; in an other pt, SRS clarified out a doubtful Tc-99m bone scan result and led to definitive confirmation of bone metastases. We had only 1 false negative result in 1 pt having pulmonary metastases (slightly positive radioiodine scan) which had been stable in size on CT for 6 years. These results indicate that, when radioiodine scans are ineffective, SRS is a powerful modality for imaging DTC tumor sites.

  6. Thyroid scintigraphy in veterinary medicine.

    PubMed

    Daniel, Gregory B; Neelis, Dana A

    2014-01-01

    Thyroid scintigraphy is performed in cats and dogs and has been used to a limited degree in other species such as the horse. Thyroid scintigraphy is most commonly used to aid in the diagnosis and treatment management of feline hyperthyroidism but is also used in the evaluation of canine hypothyroidism and canine thyroid carcinoma. This article reviews the normal scintigraphic appearance of the thyroid in the cat, the dog, and the horse and the principles of interpretation of abnormal scan results in the cat and the dog. Radioiodine is the treatment of choice for feline hyperthyroidism, and the principles of its use in the cat are reviewed. PMID:24314043

  7. Rhesus monkey platelets

    SciTech Connect

    Harbury, C.B.

    1986-03-01

    The purpose of this abstract is to describe the adenine nucleotide metabolism of Rhesus monkey platelets. Nucleotides are labelled with /sup 14/C-adenine and extracted with EDTA-ethanol (EE) and perchlorate (P). Total platelet ATP and ADP (TATP, TADP) is measured in the Holmsen Luciferase assay, and expressed in nanomoles/10/sup 8/ platelets. TR=TATP/TADP. Human platelets release 70% of their TADP, with a ratio of released ATP/ADP of 0.7. Rhesus platelets release 82% of their TADP, with a ratio of released ATP/ADP of 0.33. Thus, monkey platelets contain more ADP than human platelets. Thin layer chromatography of EE gives a metabolic ratio of 11 in human platelets and 10.5 in monkey platelets. Perchlorate extracts metabolic and actin bound ADP. The human and monkey platelets ratios were 5, indicating they contain the same proportion of actin. Thus, the extra ADP contained in monkey platelets is located in the secretory granules.

  8. Platelets in Lung Biology

    PubMed Central

    Weyrich, Andrew S.; Zimmerman, Guy A.

    2013-01-01

    Platelets and the lungs have an intimate relationship. Platelets are anucleate mammalian blood cells that continuously circulate through pulmonary vessels and that have major effector activities in hemostasis and inflammation. The lungs are reservoirs for megakaryocytes, the requisite precursor cell in thrombopoiesis, which is the intricate process by which platelets are generated. Platelets contribute to basal barrier integrity of the alveolar capillaries, which selectively restricts the transfer of water, proteins, and red blood cells out of the vessels. Platelets also contribute to pulmonary vascular repair. Although platelets bolster hemostatic and inflammatory defense of the healthy lung, experimental evidence and clinical evidence indicate that these blood cells are effectors of injury in a variety of pulmonary disorders and syndromes. Newly discovered biological capacities of platelets are being explored in the context of lung defense, disease, and remodeling. PMID:23043249

  9. Platelet Interaction with Bacteria

    PubMed Central

    Clawson, C. C.

    1973-01-01

    The interaction of several common strains of bacteria with rabbit or human platelets in vitro has been examined sequentially with scanning and transmission electron microscopy. Bacteria were added to platelets in their native plasma or to washed platelets in a balanced salt solution at ratios of about 1:1 or at low bacteria to platelet ratios (down to 1:100). The platelet-bacterial interaction (PBI) was studied with recording nephelometry. Matched samples were fixed for microscopy at various points in the aggregation response. The results support these conclusions: a) Bacteria stimulate platelet aggregation by direct contact and adhesion with the platelet surface. b) Adhesion between the two cell types requires divalent cations, occurs through fusion of normal cell-surface coats and appears identical in the presence or absence of extracellular plasma protein. c) The morphologic transformation of platelets during PBI is identical to that produced by collagen. d) During PBI the bacteria are incorporated into the forming platelet aggregates and reside predominantly intercellularly. e) Phagocytosis of bacteria by a single platelet is very rare. f) Bacteria which have resided within platelet aggregates for one hour are unaltered morphologically. g) PBI occurs even at very low bacterial numbers and produces platelet-bacterial aggregates in small numbers without stimulating generalized platelet aggregation. Methods for concentration of thrombocytopenic plasma and washing human platelets are presented. ImagesFig 6Fig 7Fig 8Fig 9Fig 10Fig 11Fig 1Fig 2Fig 12Fig 13Fig 3Fig 14Fig 4Fig 5 PMID:4632008

  10. Dipyridamole thallium-201 myocardial scintigraphy

    SciTech Connect

    Not Available

    1988-09-01

    Thallium-201 (/sup 201/Tl) myocardial scintigraphy is a sensitive technique for detecting coronary artery disease. Standardized exercise testing is the most common method for inducing myocardial stress for /sup 201/Tl imaging. Unfortunately, a significant number of patients are unable to undergo adequate treadmill or bicycle exercise. In these patients, pharmacologic stress with dipyridamole provides a safe, efficacious, and reliable alternative.

  11. Thallium 201 Scintigraphy

    PubMed Central

    McKillop, James H.

    1980-01-01

    The radioactive isotope thallium 201 behaves physiologically as a potassium analog, and when injected intravenously accumulates rapidly within the cells of many organs. Uptake of the isotope reflects both regional perfusion and sodium-potassium pump activity. The radionuclide emits 80 keV x-rays which are suitable for scintillation camera imaging. The main clinical application of 201TI scintigraphy has been in myocardial imaging. Abnormal uptake of the isotope results in a cold spot on the myocardial image. In patients with coronary artery disease, the differentiation of ischemic and infarcted myocardium is made by comparing images obtained after injecting the radionuclide at the peak of a maximal exercise test with those obtained after injection at rest. Abnormalities due to ischemia usually are seen only on the stress image whereas fixed defects in both rest and stress studies usually indicate areas of infarction or scarring. Some investigators believe that redistribution images obtained four to six hours after stress injection (without administering further 201TI) give the same information as a separate rest study. The sensitivity of stress imaging for detecting significant coronary disease is of the order of 80 percent to 95 percent, though computer processing of the images may be necessary to achieve the higher figure. The prediction of the extent of coronary disease from 201TI images is less reliable. An abnormal 201TI image is not entirely specific for coronary artery disease and the likelihood of an abnormal image being due to this diagnosis varies according to the clinical circumstances. The main clinical value of 201TI myocardial imaging is likely to be in the noninvasive screening of patients with atypical chest pain or with ambiguous findings on stress electrocardiographic tests. It has also proved useful in studying patients with variant angina or following a coronary bypass operation. It is doubtful whether the technique is clinically helpful in most

  12. Platelets and galectins

    PubMed Central

    2014-01-01

    A major function of platelets is keeping the vascular system intact. Platelet activation at sites of vascular injury leads to the formation of a hemostatic plug. Activation of platelets is therefore crucial for normal hemostasis; however, uncontrolled platelet activation may also lead to the formation of occlusive thrombi that can cause ischemic events. Although they are essential for proper hemostasis, platelet function extends to physiologic processes such as tissue repair, wound remodeling and antimicrobial host defense, or pathologic conditions such as thrombosis, atherosclerosis, chronic inflammatory diseases and cancer. Platelets can be activated by soluble molecules including thrombin, thromboxane A2 (TXA2), adenosine diphosphate (ADP), serotonin or by adhesive extracellular matrix (ECM) proteins such as von Willebrand factor (vWF) and collagen. Here we describe recent advances in the activation of platelets by non-canonical platelet agonists such as galectins. By acting either in soluble or immobilized form, these glycan-binding proteins trigger all platelet activation responses through modulation of discrete signaling pathways. We also offer new hypotheses and some speculations about the role of platelet-galectin interactions not only in hemostasis and thrombosis but also in inflammation and related diseases such as atherosclerosis and cancer. PMID:25405160

  13. Platelet function and ageing.

    PubMed

    Jones, Chris I

    2016-08-01

    There are clear age-related changes in platelet count and function, driven by changes in hematopoietic tissue, the composition of the blood and vascular health. Platelet count remains relatively stable during middle age (25-60 years old) but falls in older people. The effect of age on platelet function is slightly less clear. The longstanding view is that platelet reactivity increases with age in an almost linear fashion. There are, however, serious limitations to the data supporting this dogma. We can conclude that platelet function increases during middle age, but little evidence exists on the changes in platelet responsiveness in old age (>75 years old). This change in platelet function is driven by differential mRNA and microRNA expression, an increase in oxidative stress and changes in platelet receptors. These age-related changes in platelets are particularly pertinent given that thrombotic disease and use of anti-platelet drugs is much more prevalent in the elderly population, yet the majority of platelet research is carried out in young to middle-aged (20-50 years old) human volunteers and young mice (2-6 months old). We know relatively little about exactly how platelets from people over 75 years old differ from those of middle-aged subjects, and we know even less about the mechanisms that drive these changes. Addressing these gaps in our knowledge will provide substantial understanding in how cell signalling changes during ageing and will enable the development of more precise anti-platelet therapies. PMID:27068925

  14. In vivo dissolution measurement with indium-111 summation peak ratios

    SciTech Connect

    Jay, M.; Woodward, M.A.; Brouwer, K.R.

    1985-10-01

    Dissolution of (/sup 111/In)labeled tablets was measured in vivo in a totally noninvasive manner by using a modification of the perturbed angular correlation technique known as the summation peak ratio method. This method, which requires the incorporation of only 10-12 microCi into the dosage form, provided reliable dissolution data after oral administration of (/sup 111/In)lactose tablets. These results were supported by in vitro experiments which demonstrated that the dissolution rate as measured by the summation peak ratio method was in close agreement with the dissolution rate of salicylic acid in a (/sup 111/In)salicylic acid tablet. The method has the advantages of using only one detector, thereby avoiding the need for complex coincidence counting systems, requiring less radioactivity, and being potentially applicable to a gamma camera imaging system.

  15. Halo sign on indium-111 leukocyte scan in gangrenous cholecystitis

    SciTech Connect

    Bauman, J.M.; Boykin, M.; Hartshorne, M.F.; Cawthon, M.A.; Landry, A.J.

    1986-02-01

    A 56-year-old man with a long history of Crohn's disease was evaluated by In-111 labeled leukocyte scanning. A halo of leukocyte activity was seen around the gallbladder fossa. A gangrenous gallbladder was removed at surgery.

  16. Use of indium-111 as a red cell label

    SciTech Connect

    AuBuchon, J.P.; Brightman, A.

    1989-02-01

    To select the most promising 111In chelate for use as a second red cell (RBC) label for comparison of the survival of autologous and allogeneic cells, 49 normal RBC samples were studied in vitro after being labeled with 111In-8-hydroxyquinolinol (111In-oxine) prepared by three different methods, 111In-tropolone, and 111In-acetylacetone. Labeling efficiencies reached 99 percent and did not decline when the amount of 111In used was increased from 1.75 to 50 muCi per ml of RBCs. Storage of labeled RBCs in normal AB plasma at 4, 22, and 37 degrees C for up to 48 hours resulted in a similar rate of loss of the label from the RBCs with all labeling methods. These rates were time- and temperature-dependent and were accurate predictions of the rates found in later in vivo experimentation. Fresh RBCs from 11 subjects were labeled with 111In chelated with oxine in the presence of the RBCs or chelated with tropolone just prior to the labeling. RBC mass determinations using these autologous RBCs labeled with 111In accurately reflected the subjects' RBC masses as predicted through standard morphometric formulae. The rate of disappearance of the radionuclide after reinfusion of the autologous RBCs decreased with time. At 24 hours after reinfusion, 89.5 +/- 1.29 percent (mean +/- SEM) of the 111In-tropolone and 87.3 +/- 1.25 percent of the 111In-oxine continued in circulation. 111In is a simple and efficient agent for the labeling of RBCs for blood volume determinations and short-term survivals.

  17. Indium-111 leukocyte localization in infected prosthetic graft

    SciTech Connect

    Purnell, G.L.; Walker, C.W.; Allison, J.W.; Dalrymple, G.V. )

    1990-08-01

    Infective endocarditis can be difficult to prove, even in the face of strong clinical suspicion. A case in which standard methods of diagnosis failed to demonstrate endocarditis in a patient with recurrent Staphylococcus aureus bacteremia and porcine aortic valve is reported. An In-111 labelled leukocyte SPECT study demonstrated uptake in the aortic root and leaflets, and autopsy demonstrated vegetations on the leaflets. In-111 may prove useful in demonstrating endocarditis in patients with prosthetic valve infection.

  18. Uptake of indium-111-labeled leukocytes by brain metastasis

    SciTech Connect

    Balachandran, S.; Husain, M.M.; Adametz, J.R.; Pallin, J.S.; Angtuaco, T.L.; Boyd, C.M.

    1987-04-01

    Uptake of indium-labeled leukocytes was seen in two cases of histologically proven brain metastasis. In one, this led to misdiagnosis of the lesion as an abscess. On histological evaluation, a large number of white blood cells or macrophages was seen at the neoplastic sites. Reasons for leukocyte accumulation around metastatic brain neoplasms are discussed. In contrast to the current reports that indium-labeled leukocyte scans can differentiate intracranial infection from tumor, these cases demonstrate their lack of specificity in the detection of brain abscess.

  19. Platelets enhance neutrophil transendothelial migration

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Platelets are increasingly recognized as important mediators of inflammation in addition to thrombosis. While platelets have been shown to promote neutrophil (PMN) adhesion to endothelium in various inflammatory models, it is unclear whether platelets enhance neutrophil transmigration across inflame...

  20. Preparation and immunoreactivity of high specific activity indium-111-DTPA labeled monoclonal antibody (MoAb) using ultrapure indium-111

    SciTech Connect

    Zoghbi, S.S.; Neumann, R.D.; Gottschalk, A.

    1986-10-01

    The preparation of high-specific activity /sup 111/In-DTPA-MoAb without increasing the number of DTPA molecules per Ab was investigated. Instant thin layer chromatography was used to assay the relationship between labeling efficiencies and specific activities. With ultrapurified /sup 111/In, the specific activity of the radiolabeled MoAb approached the expected theoretic maximum of 100 muCi/microgram. The bioactivity of such high-specific activity preparation showed no degradation as measured by in vitro cell binding assay.

  1. Bone scintigraphy in diabetic osteoarthropathy

    SciTech Connect

    Eymontt, M.J.; Alavi, A.; Dalinka, M.K.; Kyle, G.C.

    1981-08-01

    Bone scans of patients with diabetic osteoarthropathy of the ankle and foot were characterized by a combination of diffuse and focal increased uptake, similar to that seen with hyperemia and reactive new bone formation. Scintigraphy showed more extensive abnormalities than radiography, with the scan abnormalities sometimes preceding the radiographic changes. The clinical and scintigraphic appearance of osteoarthropathy may improve following strict diabetic control and non-weight-bearing.

  2. Inherited platelet disorders.

    PubMed

    Sandrock-Lang, Kirstin; Wentzell, Rüdiger; Santoso, Sentot; Zieger, Barbara

    2016-08-01

    Inherited platelet disorders may be the cause of bleeding symptoms of varying severity as platelets fail to fulfil their haemostatic role after vessel injury. Platelet disorders may be difficult to diagnose (and are likely to be misdiagnosed) and raise problems in therapy and management. This review explores the clinical and molecular genetic phenotype of several inherited disorders. Inherited platelet disorders can be classified according to their platelet defects: receptor defects (adhesion or aggregation), secretion disorder, and cytoskeleton defects. The best characterized platelet receptor defects are Glanzmann thrombasthenia (integrin αIIbβ3 defect) and Bernard-Soulier syndrome (defect of GPIb/IX/V). Detailed case reports of patients suffering from Glanzmann thrombasthenia (GT) or Bernard-Soulier syndrome (BSS) showing the bleeding diathesis as well as investigation of platelet aggregation/agglutination and platelet receptor expression will complement this review. In addition, Hermansky-Pudlak syndrome (HPS) as an important defect of δ-granule secretion is extensively described together with a case report of a patient suffering from HPS type 1. PMID:25707719

  3. Platelet Function Tests

    MedlinePlus

    ... of the clotting process in the body ( in vivo ). A person with normal platelet function test results may still experience excessive bleeding or inappropriate clotting during and after a surgery. Most samples for platelet function testing are only stable for a very short period ...

  4. Platelet Donation (Apheresis)

    MedlinePlus

    ... may be ideal for a simultaneous platelet and plasma donation. Anyone in need can receive your plasma, it is universal. Only 4% of the U.S. ... can donate up to 24 times per year. Plasma can be collected simultaneously with a platelet donation. ...

  5. Incidental finding of meningioma on bone scintigraphy.

    PubMed

    Thakorlal, A; Wong, D C; Anderson, R J

    2005-06-01

    An incidental finding of an intracranial posterior fossa meningioma detected by bone scintigraphy is presented. Most of the published literature on the diagnosis of meningioma is on the use of CT and MRI. There is limited published literature on the detection of meningioma with bone scintigraphy. PMID:15932468

  6. Platelet-collagen adhesion enhances platelet aggregation induced by binding of VWF to platelets

    SciTech Connect

    Laduca, F.M.; Bell, W.R.; Bettigole, R.E. State Univ. of New York, Buffalo )

    1987-11-01

    Ristocetin-induced platelet aggregation (RIPA) was evaluated in the presence of platelet-collagen adhesion. RIPA of normal donor platelet-rich plasma (PRP) demonstrated a primary wave of aggregation mediated by the binding of von Willebrand factor (VWF) to platelets and a secondary aggregation wave, due to a platelet-release reaction, initiated by VWF-platelet binding and inhibitable by acetylsalicylic acid (ASA). An enhanced RIPA was observed in PRP samples to which collagen had been previously added. These subthreshold concentrations of collagen, which by themselves were insufficient to induce aggregation, caused measurable platelet-collagen adhesion. Subthreshold collagen did not cause microplatelet aggregation, platelet release of ({sup 3}H)serotonin, or alter the dose-responsive binding of {sup 125}I-labeled VWF to platelets, which occurred with increasing ristocetin concentrations. However, ASA inhibition of the platelet release reaction prevented collagen-enhanced RIPA. These results demonstrate that platelet-collagen adhesion altered the platelet-release reaction induced by the binding of VWF to platelets causing a platelet-release reaction at a level of VWF-platelet binding not normally initiating a secondary aggregation. These findings suggest that platelet-collagen adhesion enhances platelet function mediated by VWF.

  7. Platelet Adhesion under Flow

    PubMed Central

    Ruggeri, Zaverio M.

    2011-01-01

    Platelet adhesive mechanisms play a well-defined role in hemostasis and thrombosis, but evidence continues to emerge for a relevant contribution to other pathophysiological processes including inflammation, immune-mediated responses to microbial and viral pathogens, and cancer metastasis. Hemostasis and thrombosis are related aspects of the response to vascular injury, but the former protects from bleeding after trauma while the latter is a disease mechanism. In either situation, adhesive interactions mediated by specific membrane receptors support the initial attachment of single platelets to cellular and extracellular matrix constituents of the vessel wall and tissues. In the subsequent steps of thrombus growth and stabilization, adhesive interactions mediate platelet to platelet cohesion (aggregation) and anchoring to the fibrin clot. A key functional aspect of platelets is their ability to circulate in a quiescent state surveying the integrity of the inner vascular surface, coupled to a prompt reaction wherever alterations are detected. In many respects, therefore, platelet adhesion to vascular wall structures, to one another or to other blood cells are facets of the same fundamental biological process. The adaptation of platelet adhesive functions to the effects of blood flow is the main focus of this review. PMID:19191170

  8. Taurine and platelet aggregation

    SciTech Connect

    Nauss-Karol, C.; VanderWende, C.; Gaut, Z.N.

    1986-03-01

    Taurine is a putative neurotransmitter or neuromodulator. The endogenous taurine concentration in human platelets, determined by amino acid analysis, is 15 ..mu..M/g. In spite of this high level, taurine is actively accumulated. Uptake is saturable, Na/sup +/ and temperature dependent, and suppressed by metabolic inhibitors, structural analogues, and several classes of centrally active substances. High, medium and low affinity transport processes have been characterized, and the platelet may represent a model system for taurine transport in the CNS. When platelets were incubated with /sup 14/C-taurine for 30 minutes, then resuspended in fresh medium and reincubated for one hour, essentially all of the taurine was retained within the cells. Taurine, at concentrations ranging from 10-1000 ..mu..M, had no effect on platelet aggregation induced by ADP or epinephrine. However, taurine may have a role in platelet aggregation since 35-39% of the taurine taken up by human platelets appears to be secreted during the release reaction induced by low concentrations of either epinephrine or ADP, respectively. This release phenomenon would imply that part of the taurine taken up is stored directly in the dense bodies of the platelet.

  9. Platelet deposition at angioplasty sites and its relation to restenosis in human iliac and femoropopliteal arteries

    SciTech Connect

    Minar, E.; Ehringer, H.; Ahmadi, R.; Dudczak, R.; Leitha, T.; Koppensteiner, R.; Jung, M.; Stuempflen, A.

    1989-03-01

    The amount and time course of platelet accumulation at angioplasty sites and influence of these platelets on restenosis after percutaneous transluminal angioplasty (PTA) in peripheral arteries were determined in 92 patients, who received either a high or low dose of aspirin. Platelet deposition was quantitated by means of dual-radiotracer scintigraphy and calculation of a platelet accumulation index (PAI). The PAI was higher (P less than .05) 4-6 hours after PTA compared with that on subsequent days. There was a trend toward greater platelet accumulation in vessels with extensive dissection. Platelet accumulation at the PTA site occurred with both doses of aspirin, with no differences between the two dosage groups. Twenty-one of 67 patients who underwent PTA in the femoropopliteal segment developed restenosis during a median follow-up of 14 months. The median PAI at 4-6 and 22-24 hours after PTA was significantly less in these 21 patients than in the 46 without restenosis. The data suggest that use of antiplatelet agents to prevent platelet deposition after PTA may not be useful for prevention of restenosis.

  10. Nanotechnology: Platelet mimicry

    NASA Astrophysics Data System (ADS)

    Farokhzad, Omid C.

    2015-10-01

    Cloaking drug-loaded nanoparticles with platelet membranes enhances the drugs' abilities to target desired cells and tissues. This technology might improve treatments for cardiovascular and infectious diseases. See Letter p.118

  11. Platelet-delivered therapeutics.

    PubMed

    Lyde, R; Sabatino, D; Sullivan, S K; Poncz, M

    2015-06-01

    We have proposed that modified platelets could potentially be used to correct intrinsic platelet defects as well as for targeted delivery of therapeutic molecules to sights of vascular injury. Ectopic expression of proteins within α-granules prior to platelet activation has been achieved for several proteins, including urokinase, factor (F) VIII, and partially for FIX. Potential uses of platelet-directed therapeutics will be discussed, focusing on targeted delivery of urokinase as a thromboprophylactic agent and FVIII for the treatment of hemophilia A patients with intractable inhibitors. This presentation will discuss new strategies that may be useful in the care of patients with vascular injury as well as remaining challenges and limitations of these approaches. PMID:26149015

  12. Platelet associated antibodies

    MedlinePlus

    ... of the following: For unknown reasons (idiopathic thrombocytopenic purpura, or ITP ) Side effect of certain drugs such ... 2012:chap 134. Read More Antibody Idiopathic thrombocytopenic purpura (ITP) Platelet count Serum globulin electrophoresis Thrombocytopenia Update ...

  13. Platelets and diabetes mellitus.

    PubMed

    Santilli, Francesca; Simeone, Paola; Liani, Rossella; Davì, Giovanni

    2015-07-01

    Platelet activation plays a key role in atherothrombosis in type 2 diabetes mellitus (T2DM) and increased in vivo platelet activation with enhanced thromboxane (TX) biosynthesis has been reported in patients with impairment of glucose metabolism even in the earlier stages of disease and in the preclinical phases. In this regards, platelets appear as addresses and players carrying and transducing metabolic derangement into vascular injury. The present review critically addresses key pathophysiological aspects including (i) hyperglycemia, glycemic variability and insulin resistance as determinants and predictors of platelet activation, (ii) inflammatory mediators derived from platelets, such as soluble CD40 ligand, soluble CD36, Dickkopf-1 and probably soluble receptor for advanced glycation-end-products (sRAGE), which expand the functional repertoire of platelets from players of hemostasis and thrombosis to powerful amplifiers of inflammation by promoting the release of cytokines and chemokines, cell activation, and cell-cell interactions; (iii) molecular mechanisms underpinning the less-than-expected antithrombotic protection by aspirin (ASA), despite regular antiplatelet prophylaxis at the standard dosing regimen, and (iv) stratification of patients deserving different antiplatelet strategies, based on the metabolic phenotype. Taken together, these pathophysiological aspects may contribute to the development of promising mechanism-based therapeutic strategies to reduce the progression of atherothrombosis in diabetic subjects. PMID:25986598

  14. Radionuclide scintigraphy of bacterial nephritis

    SciTech Connect

    Conway, J.J.; Weiss, S.C.; Shkolnik, A.; Yogev, R.; Firlit, C.; Traisman, E.S.

    1984-01-01

    Pyelonephritis is a leading cause of renal failure and is expected to cost as much as three billion dollars in 1984. The diagnosis of urinary tract infection is usually not difficult. However, localization of the infection within the renal parenchyma as opposed to the collecting system is much more difficult. Flank pain, fever, bacteiuria and evidence of parenchymal involvement by intravenous urography may be absent or unrecognized particularly in the infant. Ultrasound and Nuclear Medicine are advocated as better methods to define parenchymal involvement. Such definition is important in the consideration of treatment since parenchymal involvement of the kidney carries a much more ominous potential outcome than infection restricted to within the collecting system. 38 children with a clinical diagnosis of urinary tract infection were studied. 26 of the patients demonstrated abnormal renal parenchymal findings with Gallium-67 Citrate or Tc-99m Glucoheptonate scintigraphy. Intravenous urography was notably ineffective with only 5 of the 20 interpreted as abnormal due to parenchymal disease or decreased function. 11 were entirely normal while only 5 demonstrated scars or hydronephrosis. Only 10 of 17 patients demonstrated intranvesicoureteral reflux on x-ray or nuclear cystography. Ultrasound depicted 6 of 20 patients as having parenchymal abnormalities. Seven were normal. Nonspecific findings such as dilitation of the renal pelvis or renal enlargement was noted in 11 of the 20 patients. Radionuclide Scintigraphy is the most efficacious modality to detect since acute bacterial nephritis.

  15. Platelet preservation: agitation and containers.

    PubMed

    van der Meer, Pieter F; de Korte, Dirk

    2011-06-01

    For platelets to maintain their in vitro quality and in vivo effectiveness, they need to be stored at room temperature with gentle agitation in gas-permeable containers. The mode of agitation affects the quality of the platelets, and a gentle method of agitation, either a circular or a flat bed movement, provides the best results. Tumblers or elliptical agitators induce platelet activation and subsequent damage. As long as the platelets remain in suspension, the agitation speed is not important. Agitation of the platelet concentrates ensures that the platelets are continuously oxygenated, that sufficient oxygen can enter the storage container and that excess carbon dioxide can be expelled. During transportation of platelet concentrates, nowadays over long distances where they are held without controlled agitation, platelets may tolerate a certain period without agitation. However, evidence is accumulating that during the time without agitation, local hypoxia surrounding the platelets may induce irreversible harm to the platelets. Over the decades, more gas-permeable plastics have been used to manufacture platelet containers. The use of different plastics and their influence on the platelet quality both in vitro and in vivo is discussed. The improved gas-permeability has allowed the extension of platelet storage from 3 days in the early 1980s, to currently at least 7 days. In the light of new developments, particularly the introduction of pathogen reduction techniques, the use of platelet additive solutions and the availability of improved automated separators, further (renewed) research in this area is warranted. PMID:21514232

  16. Atlas of nuclear medicine

    SciTech Connect

    Van Nostrand, D. ); Baum, S. )

    1988-01-01

    This book contains the proceeding on the atlas of nuclear medicine. Topics covered include: Radionuclide esophageal transit studies, Iodine-131 neck and chest scintigraphy, Indium-111 white blood cell imaging, and Pediatric radionuclide lymphography.

  17. Calmodulin antagonists induce platelet apoptosis.

    PubMed

    Wang, Zhicheng; Li, Suping; Shi, Quanwei; Yan, Rong; Liu, Guanglei; Dai, Kesheng

    2010-04-01

    Calmodulin (CaM) antagonists induce apoptosis in various tumor models and inhibit tumor cell invasion and metastasis, thus some of which have been extensively used as anti-cancer agents. In platelets, CaM has been found to bind directly to the cytoplasmic domains of several platelet receptors. Incubation of platelets with CaM antagonists impairs the receptors-related platelet functions. However, it is still unknown whether CaM antagonists induce platelet apoptosis. Here we show that CaM antagonists N-(6-aminohexyl)-5-chloro-1-naphthalene sulfonamide (W7), tamoxifen (TMX), and trifluoperazine (TFP) induce apoptotic events in human platelets, including depolarization of mitochondrial inner transmembrane potential, caspase-3 activation, and phosphatidylserine exposure. CaM antagonists did not incur platelet activation as detected by P-selectin surface expression and PAC-1 binding. However, ADP-, botrocetin-, and alpha-thrombin-induced platelet aggregation, platelet adhesion and spreading on von Willebrand factor surface were significantly reduced in platelets pre-treated with CaM antagonists. Furthermore, cytosolic Ca(2+) levels were obviously elevated by both W7 and TMX, and membrane-permeable Ca(2+) chelator BAPTA-AM significantly reduced apoptotic events in platelets induced by W7. Therefore, these findings indicate that CaM antagonists induce platelet apoptosis. The elevation of the cytosolic Ca(2+) levels may be involved in the regulation of CaM antagonists-induced platelet apoptosis. PMID:20172594

  18. Evaluation of biliary disease by scintigraphy

    SciTech Connect

    Ram, M.D.; Hagihara, P.F.; Kim, E.E.; Coupal, J.; Griffen, W.O.

    1981-01-01

    The value of biliary scintigraphy was studied in 180 patients with suspected biliary tract disease. Most of the patients were investigated additionally by conventional techniques such as cholecystography, cholangiography and ultrasonography. It is concluded that biliary scintigraphy is a simple and safe technique for visualization of the biliary tract. It is particularly useful in the evaluation of acute cholecystitis, in patients with iodine sensitivity obstructive from nonobstructive jaundice.

  19. Normal gallbladder scintigraphy in acute cholecystitis

    SciTech Connect

    Ohrt, H.J.; Posalaky, I.P.; Shafer, R.B.

    1983-03-01

    Normal gallbladder scintigraphy occurs in 2 to 5% of reported patients with acute cholecystitis. Gallbladder visualization is found in patients with acalculous cholecystitis and in those with recent relief of cystic duct obstruction but persistence of inflammation. A patient is reported who had clinical and pathologic findings of acute cholecystitis but normal gallbladder visualization. This reemphasizes that the diagnosis of acute cholecystitis cannot be excluded by normal gallbladder scintigraphy.

  20. Radionuclide bone scintigraphy in pediatric orthopedics

    SciTech Connect

    Conway, J.J.

    1986-12-01

    Radionuclide bone scintigraphy is highly sensitive and specific for diagnosing the musculoskeletal disorders of childhood. Conditions such as neonatal osteomyelitis, septic arthritis, diskitis of childhood, Legg-Calve-Perthes disease, the osteochondroses, the toddler's fracture, sports injuries, spondylolysis, myositis ossificians, and reflex sympathetic dystrophy are readily defined. High-quality state-of-the-art scintigraphy is essential in infants and young children. 64 references.

  1. Neonatal osteomyelitis examined by bone scintigraphy

    SciTech Connect

    Bressler, E.L.; Conway, J.J.; Weiss, S.C.

    1984-09-01

    Thirty-three infants less than six weeks of age and suspected of having osteomyelitis were examined by bone scintigraphy. Each of the 25 sites of proved osteomyelitis in 15 individuals demonstrated abnormal radionuclide localization. Ten additional scintigraphically positive but radiographically normal sites were detected. Optimal quality scintigrams of the growth plate complex and osteomyelitis in neonates appeared similar to those in older children. All neonates suspected of having osteomyelitis should be studied with bone scintigraphy following initial radiographs.

  2. Biliary scintigraphy in acute pancreatitis

    SciTech Connect

    Serafini, A.N.; Al-Sheikh, W.; Barkin, J.S.; Hourani, M.; Sfakiankis, G.; Clarke, L.P.; Ashkar, F.S.

    1982-08-01

    A prospective study was carried out in 60 patients to determine the efficacy of /sup 99m/Tc-PIPIDA scintigraphy in differentiating biliary pancreatitis from nonbiliary pancreatitis. Forty patients were classified as having biliary pancreatitis and 20 patients as having the nonbiliary type. Scintigraphic scans were divided into five main types according to the time to visualization of the gallbladder and the time to excretion of /sup 99m/Tc-PIPIDA into the intestinal tract. Normal scans were obtained on 95% of patients (19/20) with nonbiliary pancreatitis; 22.5% of patients (9/40) with biliary pancreatitis had normal scans. It is concluded that elevated amylase levels together with an abnormal biliary scan, as defined by the criteria presented here, indicate biliary pancreatitis, while a normal scan largely excludes such diagnosis.

  3. Biliary scintigraphy in acute pancreatitis

    SciTech Connect

    Serafini, A.N.; Al-Sheikh, W.; Barkin, J.S.; Hourani, M.; Sfakiankis, G.; Clarke, L.P.; Ashkar, F.S.

    1982-08-01

    A prospective study was carried out in 60 patients to determine the efficacy of /sup 99//sup m/Tc-PIPIDA scintigraphy in differentiating biliary pancreatitis from nonbiliary pancreatitis. Forty patients were classified as having biliary pancreatitis and 20 patients as having the nonbiliary type. Scintigraphic scans were divided into five main types according to the time to visualization of the gallbladder and the time to excretion of /sup 99//sup m/Tc-PIPIDA into the intestinal tract. Normal scans were obtained in 95% of patients (19/20) with nonbiliary pancreatitis; 22.5% of patients (9/40) with biliary pancreatitis had normal scans. It is concluded that elevated amylase levels together with an abnormal biliary scan, as defined by the criteria presented here, indicate biliary pancreatitis, while a normal scan largely excludes such diagnosis.

  4. Polyphosphate, Platelets, and Coagulation

    PubMed Central

    Travers, Richard J.; Smith, Stephanie A.; Morrissey, James H.

    2015-01-01

    While we have understood the basic outline of the enzymes and reactions that make up the traditional blood coagulation cascade for many years, recently our appreciation of the complexity of these interactions has greatly increased. This has resulted in unofficial “revisions” of the coagulation cascade to include new amplification pathways and connections between the standard coagulation cascade enzymes, as well as the identification of extensive connections between the immune system and the coagulation cascade. The discovery that polyphosphate is stored in platelet dense granules and is secreted during platelet activation has resulted in a recent burst of interest in the role of this ancient molecule in human biology. Here we review the increasingly complex role of platelet polyphosphate in hemostasis, thrombosis, and inflammation that has been uncovered in recent years, as well as novel therapeutics centered on modulating polyphosphate’s roles in coagulation and inflammation. PMID:25976958

  5. Noninvasive detection of coronary thrombi with /sup 111/In platelets: concise communication

    SciTech Connect

    Bergmann, S.R.; Lerch, R.A.; Mathias, C.J.; Sobel, B.E.; Welch, M.J.

    1983-02-01

    The need for rapid, definitive identification of coronary thrombosis has been intensified by the advent of thrombolytic therapy and by interest in the role of thrombosis in the etiology of coronary artery disease. To determine whether platelet thrombi can be detected noninvasively with /sup 111/In platelets, a method was developed in which /sup 99m/Tc-tagged red blood cells were used to correct for activity within the blood attributable to platelets circulating but not associated with thrombus. In 18 dogs coronary thrombi were induced closed-chest with a copper coil introduced into the coronary artery. /sup 111/In platelets and /sup 99m/Tc RBCs were administered either before or 1 hr after induction of thrombus, and serial scintigrams obtained. Coronary thrombus was identified readily in the processed scintigrams. In six dogs, thrombolysis was achieved with intracoronary streptokinase. In each case serial scintigraphy demonstrated resolution of the clot. The dual radiotracer technique should permit serial noninvasive delineation of the temporal relationship between platelet deposition and coronary heart disease in patients, and should facilitate the evaluation of interventions designed to prevent platelet aggregation or to lyse existing thrombi.

  6. Different effects of bleeding and soft-tissue trauma on pulmonary platelet trapping in pigs

    SciTech Connect

    Blomquist, S.; Thoerne, J.E.; Elmer, O.

    1989-06-01

    Immediate reactions to different types of trauma have been the object of several studies recently. It has been shown that pulmonary platelet trapping (PPT) occurs within minutes after both septic shock and soft-tissue trauma. The purpose of this study was to investigate whether hypovolemia induced by hypoperfusion might trigger platelet trapping in the lungs in the same way as soft-tissue trauma. Platelets labelled with indium-oxine were reinfused in anesthetized and mechanically ventilated pigs 4 hours before either induction of standardized hypovolemia caused by bleeding to the amount of 20% of the estimated blood volume (n = 6) or a standardized soft-tissue trauma to the hind limbs (n = 7). Platelet sequestration in the lungs was recorded dynamically by means of scintigraphy for 15 minutes before and 90 min after the start of the trauma and bleeding episodes. Central hemodynamics were recorded using a Swan-Ganz catheter. Soft-tissue trauma induced a marked PPT; in the animals subjected to bleeding alone there was no such effect despite a hemodynamic deterioration of greater magnitude than in the trauma group. The PPT was accompanied by a reduction in the number of platelets and leukocytes in peripheral blood. Our results indicate that immediate trapping of platelets in the lungs after trauma occurs as a response to factors other than those related to simple hypovolemic hypoperfusion.

  7. Approaches to synthetic platelet analogs.

    PubMed

    Modery-Pawlowski, Christa L; Tian, Lewis L; Pan, Victor; McCrae, Keith R; Mitragotri, Samir; Sen Gupta, Anirban

    2013-01-01

    Platelet transfusion is routinely used for treating bleeding complications in patients with hematologic or oncologic clotting disorders, chemo/radiotherapy-induced myelosuppression, trauma and surgery. Currently, these transfusions mostly use allogeneic platelet concentrates, while products like lyophilized platelets, cold-stored platelets and infusible platelet membranes are under investigation. These natural platelet-based products pose considerable risks of contamination, resulting in short shelf-life (3-5 days). Recent advances in pathogen reduction technologies have increased shelf-life to ~7 days. Furthermore, natural platelets are short in supply and also cause several biological side effects. Hence, there is significant clinical interest in platelet-mimetic synthetic analogs that can allow long storage-life and minimum side effects. Accordingly, several designs have been studied which decorate synthetic particles with motifs that promote platelet-mimetic adhesion or aggregation. Recent refinement in this design involves combining the adhesion and aggregation functionalities on a single particle platform. Further refinement is being focused on constructing particles that also mimic natural platelet's shape, size and elasticity, to influence margination and wall-interaction. The optimum design of a synthetic platelet analog would require efficient integration of platelet's physico-mechanical properties and biological functionalities. We present a comprehensive review of these approaches and provide our opinion regarding the future directions of this research. PMID:23092864

  8. Effects of platelet inhibitors on propyl gallate-induced platelet aggregation, protein tyrosine phosphorylation, and platelet factor 3 activation.

    PubMed

    Xiao, Hongyan; Kovics, Richard; Jackson, Van; Remick, Daniel G

    2004-04-01

    Propyl gallate (PG) is a platelet agonist characterized by inducing platelet aggregation, protein tyrosine phosphorylation, and platelet factor 3 activity. The mechanisms of platelet activation following PG stimulation were examined by pre-incubating platelets with well-defined platelet inhibitors using platelet aggregation, protein tyrosine phosphorylation, activated plasma clotting time, and annexin V binding by flow cytometry. PG-induced platelet aggregation and tyrosine phosphorylation of multiple proteins were substantially abolished by aspirin, apyrase, and abciximab (c7E3), suggesting that PG is associated with activation of platelet cyclooxygenase 1, adenosine phosphate receptors, and glycoprotein IIb/IIIa, respectively. The phosphorylation of the cytoskeletal enzyme pp60(c-src) increased following PG stimulation, but was blunted by pre-incubation of platelets with aspirin, apyrase, and c7E3, suggesting that tyrosine kinase is important for the signal transduction of platelet aggregation. Propyl gallate also activates platelet factor 3 by decreasing the platelet coagulation time and increasing platelet annexin V binding. Platelet incubation with aspirin, apyrase, and c7E3 did not alter PG-induced platelet coagulation and annexin V binding. The results suggest that platelet factor 3 activation and membrane phosphotidylserine expression were not involved with activation of platelet cyclooxygenase, adenosine phosphate receptors, and glycoprotein IIb/IIIa. PG is unique in its ability to stimulate platelet aggregation and coagulation simultaneously, and platelet inhibitors in this study affect only platelet aggregation but not platelet coagulation. PMID:15060414

  9. Platelet transport in microchannels

    NASA Astrophysics Data System (ADS)

    Reyssat, Mathilde; Le Goff, Anne; Blin, Antoine; Pujos, Justine; Magniez, Aurélie; Baruch, Dominique

    2013-11-01

    Blood platelets are small enucleated cells responsible for the arrest of bleeding. These cells have the ability to tether and translocate on injured vascular endothelium, thanks to a specific interaction between a receptor of their membrane and a protein expressed by the cells composing the inner wall of the vessel, the von Willebrand factor (VWF). Others cells have such abilities of rolling. Leucocytes, for example, translocate on surface due to a specific interaction between selectin molecules and their respective glycoprotein ligands. These kinds of cells present two modes of transport: they can either be advected by the flux, or translocate on surfaces due to specific ligand-receptor interactions. Our work consists first in studying experimentally the transport of platelets along a microchannel and then in modeling this particular cell transport. Due to these two modes of transport along a channel, platelets adhering to the surface are not equally distributed along the channel axis. We describe the evolution of the density of platelets with time and distance.

  10. Hysterosalpingo-radionuclide scintigraphy (HERS)

    SciTech Connect

    Iturralde, M.; Venter, P.F.

    1981-10-01

    A radionuclide procedure, hysterosalpingo-radionuclide scintigraphy (HERS), was designed to evaluate the migration of a particulate radioactive tracer from the vagina to the peritoneal cavity and ovaries as well as to image and functionally outline the patency of the pathways between these two extremes of the female reproductive system. Technetium-99m human albumin microspheres (99mTc-HAM) were deposited in the posterior fornices of patients who were divided into two specific groups. Group I consisted of patients who were to undergo different elective gynecologic operations, in which besides obtaining sequential images, radioactivity levels were measured in the removed organs and tissues. Group II consisted of patients referred by the Infertility Clinic for evaluation of their reproductive system pathways patency. In this latter group, HERS was compared with contrast hysterosalpingography (HSG) and peritoneoscopy (PCP). The results obtained from measurements of radioactivity levels on the removed surgical specimens and comparison with other conventional gynecologic diagnostic procedures provide accurate evidence of the migration of 99mTc-HAM from the vagina, through the uterus and tubes, to the peritoneal cavity and ovaries, and show that HERS is a simple noninvasive method for functionally imaging and assessing the patency of the female reproductive system pathways.

  11. Platelet satellitism: an ultrastructural study.

    PubMed Central

    Payne, C. M.

    1981-01-01

    The ultrastructural morphology of platelet-polymorph (platelet-polymorphonuclear leukocyte) rosettes was investigated in EDTA-anticoagulated blood obtained from two patients who exhibited the phenomenon of platelet satellitism. Most of the platelet profiles were attached to the polymorph surface by broad areas of contact. Examination of these broad areas of contact at high magnification revealed an intercellular material of low electron density. This material appeared to form strands, which bridged the intercellular space and spanned the entire area formed by the apposing plasma membranes. Phagocytosis of entire platelets was only observed in 1 case. The platelet profiles that participated in rosette formation revealed a large number of glycogen particles, compared with unattached platelets. Ultrastructural examination of "stress" platelets obtained from five normal subjects treated with steroids similarly showed a large number of glycogen particles, although no rosette formation or phagocytosis of platelets was observed. The etiology of platelet satellitism is discussed. Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 PMID:7223859

  12. Dietary manipulation of platelet function.

    PubMed

    Bachmair, E M; Ostertag, L M; Zhang, X; de Roos, B

    2014-11-01

    Activated platelets contribute to plaque formation within blood vessels in the early and late stages of atherogenesis, and therefore they have been proposed as risk factor for cardiovascular disease. Anti-platelet drugs, such as aspirin, are now the most prescribed pharmacological treatment in Europe. Certain dietary bioactives also beneficially affect platelet function, and with less side effects, albeit that effects are generally more subtle. Therefore, consumption of dietary bioactives could play a role in the prevention of atherothrombotic vascular disease. Here we review the efficacy of dietary treatment strategies, especially those involving certain dietary fatty acids and polyphenols, to modulate platelet function in healthy subjects or in patients with cardiovascular disease. Variation in study populations, small study sizes and lack of comparability between methods to assess platelet function currently limit robust evidence on the efficacy of dietary bioactives in healthy subjects or specific patient groups. Also, limited knowledge of the metabolism of dietary bioactives, and therefore of the bioavailability of bioactive ingredients, restricts our ability to identify the most effective dietary regimes to improve platelet function. Implementation of uniform point-of-care tests to assess platelet function, and enhanced knowledge of the efficacy by which specific dietary compounds and their metabolites affect platelet function, may enable the identification of functional anti-platelet ingredients that are eligible for a health claim, or combined treatment strategies, including both pharmacological anti-platelet treatment as well as dietary intervention, to tackle atherothrombotic vascular disease. PMID:24858060

  13. Simultaneous pancreatic-renal transplant scintigraphy

    SciTech Connect

    Shulkin, B.L.; Dafoe, D.C.; Wahl, R.L.

    1986-12-01

    99mTc-DTPA scintigraphy was evaluated in seven patients as a technique to assess perfusion of the transplanted pancreas and kidney. Such scans provide high-quality images of both organs in both the flow phase and later phases. The radionuclide is readily available and its brief effective half-life allows repeated evaluations at short intervals. /sup 131/I-hippuran, the major radiopharmaceutical for renal transplant scintigraphy, does not allow visualization of the transplanted pancreas or evaluation of its blood supply. Although the blood glucose is a gross indicator of the function of the pancreatic allograft, pancreatic scintigraphy with 99mTc-DTPA in one case was capable of detecting graft dysfunction before elevation of the blood glucose occurred. While additional studies will be necessary to determine the predictive value of this test, 99mTc-DTPA is valuable for pancreatic-renal transplant evaluation.

  14. Findings of Bone Scintigraphy After Leech Theraphy

    PubMed Central

    Özyurt, Sinem; Koca, Gökhan; Demirel, Koray; Baskın, Aylin; Korkmaz, Meliha

    2014-01-01

    In this case report, we present a 70 year old female patient who had recieved Leech therapy (hirudotherapy) on her leg without informing referring physician. In dynamic bone scintigraphy there was increased perfusion and hyperemia in her left ankle and leg, also in late static images moderate increased uptake was seen in soft tissue region and at the fracture site of ankle. We learned that she had Leech therapy applied on her leg, which could explain the increased perfusion and hyperemia in dynamic and blood pool phases of bone scintigraphy because of Leech therapy’s dilatory effects on superficial veins. Leech therapy may lead to an increase in perfusion and hyperemia in blood pool phase of bone scintigraphy, which may cause confusion in differential diagnosis. To our best knowledge this report is the first case that shows the scintigraphic findigs after Leech therapy. Conflict of interest:None declared. PMID:24653932

  15. Guidelines for radioiodinated MIBG scintigraphy in children.

    PubMed

    Olivier, Pierre; Colarinha, Paula; Fettich, Jure; Fischer, Sibylle; Frökier, Jörgen; Giammarile, Francesco; Gordon, Isky; Hahn, Klaus; Kabasakal, Levent; Mann, Mike; Mitjavila, Mercedes; Piepsz, Amy; Porn, Ute; Sixt, Rune; van Velzen, Jeannette

    2003-05-01

    These guidelines on the use of radioiodinated (99m)Tc-MIBG scintigraphy in children, which summarise the views of the Paediatric Committee of the European Association of Nuclear Medicine, provide a framework which may prove helpful to nuclear medicine teams in daily practice. They have been influenced by the conclusions of the "Consensus Guidelines for MIBG Scintigraphy" (Paris, November 6, 1997) of the European Neuroblastoma Group and by those of the Oncological Committee of the French Society of Nuclear Medicine. The guidelines should be taken in the context of "good practice" and any local/national rules which apply to nuclear medicine examinations. PMID:12658506

  16. Incidental Warthin Tumor on Pertechnetate Scintigraphy.

    PubMed

    Kulkarni, Mukta; Shetkar, Shubhangi; Joshi, Prathamesh; Kasaliwal, Sanket; Chaudhari, Shrikant

    2016-09-01

    A 30-year-old woman underwent Tc-pertechnetate scintigraphy for evaluation of thyrotoxicosis. The scintigraphy revealed hypervascular thyroid gland with markedly increased trapping function in both the lobes suggesting diagnosis of Graves disease. Incidentally, a hypervascular and pertechnetate avid focus was seen along the lateral margin of the right parotid gland. Pertechnetate avidity and site of uptake suggested possibility of Warthin tumor. Clinical examination and ultrasonography revealed a well-defined lesion in the superficial lobe of the right parotid gland favoring diagnosis of benign lesion. Postsurgery specimen confirmed diagnosis of Warthin tumor. PMID:27405035

  17. Platelet Immobilization on Supported Phospholipid Bilayers for Single Platelet Studies.

    PubMed

    Uhl, Eva; Donati, Alessia; Reviakine, Ilya

    2016-08-23

    The worldwide cardiovascular disease (CVD) epidemic is of grave concern. A major role in the etiology of CVDs is played by the platelets (thrombocytes). Platelets are anuclear cell fragments circulating in the blood. Their primary function is to catalyze clot formation, limiting traumatic blood loss in the case of injury. The same process leads to thrombosis in the case of CVDs, which are commonly managed with antiplatelet therapy. Platelets also have other, nonhemostatic functions in wound healing, inflammation, and tissue regeneration. They play a role in the early stages of atherosclerosis and the spread of cancer through metastases. Much remains to be learned about the regulation of these diverse platelet functions under physiological and pathological conditions. Breakthroughs in this regard are expected to come from single platelet studies and systems approaches. The immobilization of platelets at surfaces is advantageous for developing such approaches, but platelets are activated when they come in contact with foreign surfaces. In this work, we develop and validate a protocol for immobilizing platelets on supported lipid bilayers without activation due to immobilization. Our protocol can therefore be used for studying platelets with a wide variety of surface-sensitive techniques. PMID:27438059

  18. Platelets in Inflammation and Atherogenesis

    PubMed Central

    Nording, Henry M.; Seizer, Peter; Langer, Harald F.

    2015-01-01

    Platelets contribute to processes beyond thrombus formation and may play a so far underestimated role as an immune cell in various circumstances. This review outlines immune functions of platelets in host defense, but also how they may contribute to mechanisms of infectious diseases. A particular emphasis is placed on the interaction of platelets with other immune cells. Furthermore, this article outlines the features of atherosclerosis as an inflammatory vascular disease highlighting the role of platelet crosstalk with cellular and soluble factors involved in atheroprogression. Understanding, how platelets influence these processes of vascular remodeling will shed light on their role for tissue homeostasis beyond intravascular thrombosis. Finally, translational implications of platelet-mediated inflammation in atherosclerosis are discussed. PMID:25798138

  19. Human blood platelets at microgravity

    NASA Technical Reports Server (NTRS)

    Surgenor, D. MACN.; Ausprunk, D.; Blevins, D.; Chao, F. C.; Curby, W.

    1987-01-01

    A set of freshly collected and separated human platelet suspensions were transported, in three types of plastic containers, on a 6 day, 2 hr mission of the orbiter Columbia to study the effect of prolonged exposure of human blood cells to microgravity. A controlled environment at a temperature of 22 + or - 1 deg with air flow was provided and another set of samples held on the ground acted as controls. Paired comparisons of platelets at ug versus controls at lxg revealed superior platelet survival at microgravity. When viewed in terms of plastic type, ug platelets in containers fabricated from PVC-TOTM displayed the best overall postflight viability.

  20. Overview of platelet physiology and laboratory evaluation of platelet function.

    PubMed

    Rodgers, G M

    1999-06-01

    Appropriate laboratory testing for the platelet-type bleeding disorders hinges on an adequate assessment in the history and physical examination. Patients with histories and screening laboratory results consistent with coagulation disorders (hemophilia, disseminated intravascular coagulation) are not appropriate candidates for platelet function testing. In contrast, patients with a lifelong history of platelet-type bleeding symptoms and perhaps a positive family history of bleeding would be appropriate for testing. Figure 6 depicts one strategy to evaluate these patients. Platelet morphology can easily be evaluated to screen for two uncommon qualitative platelet disorders: Bernard-Soulier syndrome (associated with giant platelets) and gray platelet syndrome, a subtype of storage pool disorder in which platelet granulation is morphologically abnormal by light microscopy. If the bleeding disorder occurred later in life (no bleeding with surgery or trauma early in life), the focus should be on acquired disorders of platelet function. For those patients thought to have an inherited disorder, testing for vWD should be done initially because approximately 1% of the population has vWD. The complete vWD panel (factor VIII coagulant activity, vWf antigen, ristocetin cofactor activity) should be performed because many patients will have abnormalities of only one particular panel component. Patients diagnosed with vWD should be classified using multimeric analysis to identify the type 1 vWD patients likely to respond to DDAVP. If vWD studies are normal, platelet aggregation testing should be performed, ensuring that no antiplatelet medications have been ingested at least 1 week before testing. If platelet aggregation tests are normal and if suspicion for an inherited disorder remains high, vWD testing should be repeated. The evaluation of thrombocytopenia may require bone marrow examination to exclude primary hematologic disorders. If future studies with thrombopoietin assays

  1. Subpopulations in purified platelets adhering on glass.

    PubMed

    Donati, Alessia; Gupta, Swati; Reviakine, Ilya

    2016-01-01

    Understanding how platelet activation is regulated is important in the context of cardiovascular disorders and their management with antiplatelet therapy. Recent evidence points to different platelet subpopulations performing different functions. In particular, procoagulant and aggregating subpopulations have been reported in the literature in platelets treated with the GPVI agonists. How the formation of platelet subpopulations upon activation is regulated remains unclear. Here, it is shown that procoagulant and aggregating platelet subpopulations arise spontaneously upon adhesion of purified platelets on clean glass surfaces. Calcium ionophore treatment of the adhering platelets resulted in one platelet population expressing both the procoagulant and the adherent population markers phosphatidylserine and the activated form of GPIIb/IIIa, while all of the platelets expressed CD62P independently of the ionophore treatment. Therefore, all platelets have the capacity to express all three activation markers. It is concluded that platelet subpopulations observed in various studies reflect the dynamics of the platelet activation process. PMID:27338300

  2. Bone scintigraphy in the diagnosis of mastoiditis

    SciTech Connect

    Floyd, J.L.; Goodman, E.L.

    1981-07-01

    Bone scintigraphy has proven utility in the early diagnosis of osteomyelitis, but the authors were unable to find any report of its specific application to mastoiditis. Three cases of mastoiditis are presented in which the bone scan findings predicted the histopathologic findings.

  3. [STRUCTURAL CHARACTERIZATION OF PLATELETS AND PLATELET-DERIVED MICROVESICLES].

    PubMed

    Ponomareva, A A; Nevzorova, T A; Mordakhanova, E R; Andrianova, I A; Litvinov, R I

    2016-01-01

    Platelets are the anucleated blood cells, wich together with the fibrin stop bleeding (hemostasis). Cellular microvesicles are membrane-surrounded microparticles released into extracellular space upon activation and/or apoptosis of various cells. Platelet-derived macrovesicles from the major population of circulating blood microparticles that play an important role in hemostasis and thrombosis. Despite numerous studies on the pathophysiology of platelet-derived macrovesicles, mechanisms of their formation and structural details remain poorly understood. Here we investigated the ultrastructure of parental platelets and platelet-derived microvesicles formed in vitro by quiescent cells as well as by cells stimulated with one of the following activators: arachidonic acid, ADP, thrombin, calcium ionophore A23187. Using transmission electron microscopy of human platelets and isolated microvesicles, we analyzed the intracellular origin, steps of formation, structural diversity, and size distributions of the subcellular particles. We have revealed that thrombin, unlike other stimuli, not only induced vesiculation of the plasma membrane but also caused break-up of the cells followed by formation of microparticles that are comparable with microvesicles by size. A fraction of these microparticles contained cellular organelles surrounded by a thin membrane. The size of platelet-derived macrovesicles varied from 30 nm to 500 nm, however, the size distributions depended on the nature of a cell-activating stimulus. The results obtained provide new information about the formation of platelet-derived macrovesicles and their structural diversity, wich is important to understand their multiple functions in normal and disease states. PMID:27228656

  4. Myocardial perfusion scintigraphy: the evidence.

    PubMed

    Underwood, S R; Anagnostopoulos, C; Cerqueira, M; Ell, P J; Flint, E J; Harbinson, M; Kelion, A D; Al-Mohammad, A; Prvulovich, E M; Shaw, L J; Tweddel, A C

    2004-02-01

    This review summarises the evidence for the role of myocardial perfusion scintigraphy (MPS) in patients with known or suspected coronary artery disease. It is the product of a consensus conference organised by the British Cardiac Society, the British Nuclear Cardiology Society and the British Nuclear Medicine Society and is endorsed by the Royal College of Physicians of London and the Royal College of Radiologists. It was used to inform the UK National Institute of Clinical Excellence in their appraisal of MPS in patients with chest pain and myocardial infarction. MPS is a well-established, non-invasive imaging technique with a large body of evidence to support its effectiveness in the diagnosis and management of angina and myocardial infarction. It is more accurate than the exercise ECG in detecting myocardial ischaemia and it is the single most powerful technique for predicting future coronary events. The high diagnostic accuracy of MPS allows reliable risk stratification and guides the selection of patients for further interventions, such as revascularisation. This in turn allows more appropriate utilisation of resources, with the potential for both improved clinical outcomes and greater cost-effectiveness. Evidence from modelling and observational studies supports the enhanced cost-effectiveness associated with MPS use. In patients presenting with stable or acute chest pain, strategies of investigation involving MPS are more cost-effective than those not using the technique. MPS also has particular advantages over alternative techniques in the management of a number of patient subgroups, including women, the elderly and those with diabetes, and its use will have a favourable impact on cost-effectiveness in these groups. MPS is already an integral part of many clinical guidelines for the investigation and management of angina and myocardial infarction. However, the technique is underutilised in the UK, as judged by the inappropriately long waiting times and by

  5. Genomics of platelet disorders.

    PubMed

    Westbury, S K; Mumford, A D

    2016-07-01

    Genetic diagnosis in families with inherited platelet disorders (IPD) is not performed widely because of the genetic heterogeneity of this group of disorders and because in most cases, it is not possible to select single candidate genes for analysis using clinical and laboratory phenotypes. Next-generation sequencing (NGS) technology has revolutionized the scale and cost-effectiveness of genetic testing, and has emerged as a valuable tool for IPD. This review examines the potential utility of NGS as a diagnostic tool to streamline detection of causal variants in known IPD genes and as a vehicle for new gene discovery. PMID:27405671

  6. Platelet abnormalities in nephrotic syndrome.

    PubMed

    Eneman, Benedicte; Levtchenko, Elena; van den Heuvel, Bert; Van Geet, Chris; Freson, Kathleen

    2016-08-01

    Nephrotic syndrome (NS) is a common kidney disease associated with a significantly increased risk of thrombotic events. Alterations in plasma levels of pro- and anti-coagulant factors are involved in the pathophysiology of venous thrombosis in NS. However, the fact that the risk of both venous and arterial thrombosis is elevated in NS points to an additional role for blood platelets. Increased platelet counts and platelet hyperactivity have been observed in nephrotic children. Platelet hyperaggregability, increased release of active substances, and elevated surface expression of activation-dependent platelet markers have been documented. The mechanisms underlying those platelet alterations are multifactorial and are probably due to changes in plasma levels of platelet-interfering proteins and lipid changes, as a consequence of nephrosis. The causal relationship between platelet alterations seen in NS and the occurrence of thromboembolic phenomena remains unclear. Moreover, the efficiency of prophylactic treatment using antiplatelet agents for the prevention of thrombotic complications in nephrotic patients is also unknown. Thus, antiplatelet medication is currently not generally recommended for routine prophylactic therapy. PMID:26267676

  7. Platelet adhesiveness in diabetes mellitus

    PubMed Central

    Shaw, S.; Pegrum, G. D.; Wolff, Sylvia; Ashton, W. L.

    1967-01-01

    Platelet adhesiveness has been assessed on whole blood from a series of 34 diabetics and 50 control subjects using adenosine diphosphate (A.D.P.) and by adherence to glass microspherules (ballotini). Using both techniques it was possible to demonstrate a significant increase in platelet adhesiveness in the diabetic patients. PMID:5614070

  8. Platelets: production, morphology and ultrastructure.

    PubMed

    Thon, Jonathan N; Italiano, Joseph E

    2012-01-01

    Platelets are anucleate, discoid cells, roughly 2-3 μm in diameter that function primarily as regulators of hemostasis, but also play secondary roles in angiogensis and innate immunity. Although human adults contain nearly one trillion platelets in circulation that are turned over every 8-10 days, our understanding of the mechanisms involved in platelet production is still incomplete. Platelets stem from large (30-100 μm) nucleated cells called megakaryocytes that reside primarily in the bone marrow. During maturation megakaryocytes extend long proplatelet elongations into sinusoidal blood vessels from which platelets ultimately release. During this process, platelets develop a number of distinguishable structural elements including: a delimited plasma membrane; invaginations of the surface membrane that form the open canalicular system (OCS); a closed-channel network of residual endoplasmic reticulum that form the dense tubular system (DTS); a spectrin-based membrane skeleton; an actin-based cytoskeletal network; a peripheral band of microtubules; and numerous organelles including α-granules, dense-granules, peroxisomes, lysosomes, and mitochondria. Proplatelet elongation and platelet production is an elaborate and complex process that defines the morphology and ultrastructure of circulating platelets, and is critical in understanding their increasingly numerous and varied biological functions. PMID:22918725

  9. Biologic nanoparticles and platelet reactivity

    PubMed Central

    Miller, Virginia M; Hunter, Larry W; Chu, Kevin; Kaul, Vivasvat; Squillace, Phillip D; Lieske, John C; Jayachandran, Muthuvel

    2009-01-01

    Aim Nanosized particles (NPs) enriched in hydroxyapatite and protein isolated from calcified human tissue accelerate occlusion of endothelium-denuded arteries when injected intravenously into rabbits. Since platelet aggregation and secretory processes participate in normal hemostasis, thrombosis and vascular remodeling, experiments were designed to determine if these biologic NPs alter specific platelet functions in vitro. Methods Platelet-rich plasma was prepared from citrate anticoagulated human blood. Platelet aggregation and ATP secretion were monitored in response to thrombin receptor agonists peptide (10 μM) or convulxin (50 μg/ml) prior to and following 15 min incubation with either control solution, human-derived NPs, bovine-derived NPs or crystals of hydroxyapatite at concentrations of 50 and 150 nephelometric turbidity units. Results Incubation of platelets for 15 min with either human- or bovine-derived NPs reduced aggregation induced by thrombin receptor activator peptide and convulxin in a concentration-dependent manner. Hydroxyapatite caused a greater inhibition than either of the biologically derived NPs. Human-derived NPs increased ATP secretion by unstimulated platelets during the 15 min incubation period. Conclusion Effects of bovine-derived and hydroxyapatite NPs on basal release of ATP were both time and concentration dependent. These results suggest that biologic NPs modulate both platelet aggregation and secretion. Biologically derived NPs could modify platelet responses within the vasculature, thereby reducing blood coagulability and the vascular response to injury. PMID:19839809

  10. Platelet-Rich Plasma

    PubMed Central

    Cole, Brian J.; Seroyer, Shane T.; Filardo, Giuseppe; Bajaj, Sarvottam; Fortier, Lisa A.

    2010-01-01

    Context: Platelet-rich plasma (PRP) may affect soft tissue healing via growth factors released after platelet degranulation. Because of this potential benefit, clinicians have begun to inject PRP for the treatment of tendon, ligament, muscle, and cartilage injuries and early osteoarthritis. Evidence Acquisition: A PubMed search was performed for studies relating to PRP, growth factors, and soft tissue injuries from 1990 to 2010. Relevant references from these studies were also retrieved. Results: Soft tissue injury is a major source of disability that may often be complicated by prolonged and incomplete recovery. Numerous growth factors may potentiate the healing and regeneration of tendons and ligaments. The potential benefits of biologically enhanced healing processes have led to a recent interest in the use of PRP in orthopaedic sports medicine. There has been widespread anecdotal use of PRP for muscle strains, tendinopathy, and ligament injuries and as a surgical adjuvant to rotator cuff repair, anterior cruciate ligament reconstruction, and meniscal or labral repairs. Although the fascination with this emerging technology has led to a dramatic increase in its use, scientific data supporting this use are still in their infancy. Conclusions: The literature is replete with studies on the basic science of growth factors and their relation to the maintenance, proliferation, and regeneration of various tissues and tissue-derived cells. Despite the promising results of several animal studies, well-controlled human studies are lacking. PMID:23015939

  11. Platelet-Rich Plasma and Platelet Gel: A Review

    PubMed Central

    Everts, Peter A.M.; Knape, Johannes T.A.; Weibrich, Gernot; Schönberger, Jacques P.A.M.; Hoffmann, Johannes; Overdevest, Eddy P.; Box, Henk A.M.; van Zundert, André

    2006-01-01

    Abstract: Strategies to reduce blood loss and transfusion of allogeneic blood products during surgical procedures are important in modern times. The most important and well-known autologous techniques are preoperative autologous predonation, hemodilution, perioperative red cell salvage, postoperative wound blood autotransfusion, and pharmacologic modulation of the hemostatic process. At present, new developments in the preparation of preoperative autologous blood component therapy by whole blood platelet-rich plasma (PRP) and platelet-poor plasma (PPP) sequestration have evolved. This technique has been proven to reduce the number of allogeneic blood transfusions during open heart surgery and orthopedic operations. Moreover, platelet gel and fibrin sealant derived from PRP and PPP mixed with thrombin, respectively, can be exogenously applied to tissues to promote wound healing, bone growth, and tissue sealing. However, to our disappointment, not many well-designed scientific studies are available, and many anecdotic stories exist, whereas questions remain to be answered. We therefore decided to study perioperative blood management in more detail with emphasis on the application and production of autologous platelet gel and the use of fibrin sealant. This review addresses a large variety of aspects relevant to platelets, platelet-rich plasma, and the application of platelet gel. In addition, an overview of recent animal and human studies is presented. PMID:16921694

  12. Radioiodine therapy of hyperthyroidism precludes thallium-201 myocardial scintigraphy

    SciTech Connect

    Orzel, J.A.; Kruyer, W.B.; Borchert, R.D.

    1987-02-01

    The authors attempted to perform Tl-201 myocardial perfusion scintigraphy in a 42-year-old man 23 and 35 days after he received 9.8 mCi of oral I-131 for documented Graves' disease. Interference from primary and scattered photons from residual thyroid I-131 made Tl-201 myocardial scintigraphy technically impossible. A series of phantom and patient studies using I-131 and Tl-201 were performed, yielding guidelines for planning Tl-201 myocardial scintigraphy following radioiodine therapy.

  13. Limitations of indium leukocyte imaging for the diagnosis of spine infections

    SciTech Connect

    Whalen, J.L.; Brown, M.L.; McLeod, R.; Fitzgerald, R.H. Jr. )

    1991-02-01

    The usefulness of indium-111 white blood cell (WBC) scintigraphy in the detection of spine sepsis was studied in 22 patients who had open or percutaneous biopsies for microbiologic diagnosis. The indium images in 18 patients with vertebral infection were falsely negative in 15 (83%) and truly positive in 3 (17%). All four patients with negative cultures and histology had true-negative scans. The indium-111 WBC imaging results yielded a sensitivity of 17%, a specificity of 100%, and an accuracy rate of 31%. Prior antibiotic therapy was correlated with a high incidence of false-negative scans and photon-deficient indium-111 WBC uptake. The usefulness of indium-111 WBC scintigraphy for the diagnosis of vertebral infection may be limited to those patients who have not been treated with antibiotics previously.

  14. Platelet storage media.

    PubMed

    Gulliksson, H

    2014-10-01

    Present platelet storage media often designated platelet additive solutions (PAS) basically contain acetate, citrate and phosphate and recently also potassium and magnesium. However, there seems to be an increasing interest in developing PASs that can be used also after further reduction of residual plasma content below 15-20% plasma. Inclusion of glucose but also calcium and bicarbonate in such solutions have been suggested to improve platelet (PLT) storage, especially when plasma content is reduced to very low levels. Results from a limited number of studies using novel PAS alternatives have been presented during the last years, such as InterSol-G, PAS-5, M-sol, PAS-G and SAS. Most of them are experimental solutions. The combined results presented in those studies suggest that presence of glucose may be necessary during PLT storage, primarily to maintain ATP at acceptable levels. At plasma inclusion below 15-20%, the content of glucose will generally be too low to support PLT metabolism for more than a few days making glucose addition in PAS necessary. Significant effects associated with presence of calcium was observed in PLTs stored in PAS with 5% inclusion but not with 20-35% plasma inclusion, suggesting that the content of plasma could be of importance. Bicarbonate only seems to be of importance for pH regulation, primarily when plasma inclusion is reduced to about 5%. Reduction in rate of glycolysis was observed in some PAS alternatives containing potassium and magnesium but not in others. Differences in pH or in concentrations of the various compounds included in PAS may be possible explanations. Additionally, novel PAS containing glucose, calcium and bicarbonate does not seem to be associated with improved in vitro results as compared to SSP+ or CompoSol when PLTs are stored with 35% plasma inclusion. The results would then also suggest that excess of glucose in novel PAS environment may not be associated with additional positive effects on PLT metabolism

  15. Shiga toxin binds to activated platelets.

    PubMed

    Ghosh, S A; Polanowska-Grabowska, R K; Fujii, J; Obrig, T; Gear, A R L

    2004-03-01

    Hemolytic uremic syndrome (HUS) is associated with acute renal failure in children and can be caused by Shiga toxin (Stx)-producing Escherichia coli. Thrombocytopenia and formation of renal thrombi are characteristic of HUS, suggesting that platelet activation is involved in its pathogenesis. However, whether Shiga toxin directly activates platelets is controversial. The present study evaluates if potential platelet sensitization during isolation by different procedures influences platelet interaction with Shiga toxin. Platelets isolated from sodium citrate anticoagulated blood were exposed during washing to EDTA and higher g forces than platelets prepared from acid-citrate-dextrose (ACD) plasma. Platelet binding of Stx was significantly higher in EDTA-washed preparations relative to ACD-derived platelets. Binding of Stx was also increased with ACD-derived platelets when activated with thrombin (1 U mL-1) and exposure of the Gb3 Stx receptor was detected only on platelets subjected to EDTA, higher g forces or thrombin. EDTA-exposed platelets lost their normal discoid shape and were larger. P-selectin (CD62P) exposure was significantly increased in EDTA-washed preparations relative to ACD-derived platelets, suggesting platelet activation. Taken together, these results suggest that direct binding of Stx occurs only on 'activated' platelets rather than on resting platelets. The ability of Stx to interact with previously activated platelets may be an important element in understanding the pathogenesis of HUS. PMID:15009469

  16. Platelet Interaction with Innate Immune Cells

    PubMed Central

    Kral, Julia Barbara; Schrottmaier, Waltraud Cornelia; Salzmann, Manuel; Assinger, Alice

    2016-01-01

    Summary Beyond their traditional role in haemostasis and thrombosis, platelets are increasingly recognised as immune modulatory cells. Activated platelets and platelet-derived microparticles can bind to leukocytes, which stimulates mutual activation and results in rapid, local release of platelet-derived cytokines. Thereby platelets modulate leukocyte effector functions and contribute to inflammatory and immune responses to injury or infection. Platelets enhance leukocyte extravasation, differentiation and cytokine release. Platelet-neutrophil interactions boost oxidative burst, neutrophil extracellular trap formation and phagocytosis and play an important role in host defence. Platelet interactions with monocytes propagate their differentiation into macrophages, modulate cytokine release and attenuate macrophage functions. Depending on the underlying pathology, platelets can enhance or diminish leukocyte cytokine production, indicating that platelet-leukocyte interactions represent a fine balanced system to restrict excessive inflammation during infection. In atherosclerosis, platelet interaction with neutrophils, monocytes and dendritic cells accelerates key steps of atherogenesis by promoting leukocyte extravasation and foam cell formation. Platelet-leukocyte interactions at sites of atherosclerotic lesions destabilise atherosclerotic plaques and promote plaque rupture. Leukocytes in turn also modulate platelet function and production, which either results in enhanced platelet destruction or increased platelet production. This review aims to summarise the key effects of platelet-leukocyte interactions in inflammation, infection and atherosclerosis. PMID:27226790

  17. Radioimmune assay of human platelet prostaglandin synthetase

    SciTech Connect

    Roth, G.J.; Machuga, E.T.

    1982-02-01

    Normal platelet function depends, in part, on platelet PG synthesis. PG synthetase (cyclo-oxygenase) catalyzes the first step in PG synthesis, the formation of PGH/sub 2/ from arachidonic acid. Inhibition of the enzyme by ASA results in an abnormality in the platelet release reaction. Patients with pparent congenital abnormalities in the enzyme have been described, and the effects have been referred to as ''aspirin-like'' defects of the platelet function. These patients lack platelet PG synthetase activity, but the actual content of PG synthetase protein in these individuals' platelets is unknown. Therefore an RIA for human platelet PG synthetase would provide new information, useful in assessing the aspirin-like defects of platelet function. An RIA for human platelet PG synthetase is described. The assay utilizes a rabbit antibody directed against the enzyme and (/sup 125/I)-labelled sheep PG synthetase as antigen. The human platelet enzyme is assayed by its ability to inhibit precipitation of the (/sup 125/I)antigen. The assay is sensitive to 1 ng of enzyme. By the immune assay, human platelets contain approximately 1200 ng of PG synethetase protein per 1.5 mg of platelet protein (approximately 10/sup 9/ platelets). This content corresponds to 10,000 enzyme molecules per platelet. The assay provides a rapid and convenient assay for the human platelet enzyme, and it can be applied to the assessment of patients with apparent platelet PG synthetase (cyclo-oxygenase) deficiency.

  18. Platelet Interaction with Innate Immune Cells.

    PubMed

    Kral, Julia Barbara; Schrottmaier, Waltraud Cornelia; Salzmann, Manuel; Assinger, Alice

    2016-03-01

    Beyond their traditional role in haemostasis and thrombosis, platelets are increasingly recognised as immune modulatory cells. Activated platelets and platelet-derived microparticles can bind to leukocytes, which stimulates mutual activation and results in rapid, local release of platelet-derived cytokines. Thereby platelets modulate leukocyte effector functions and contribute to inflammatory and immune responses to injury or infection. Platelets enhance leukocyte extravasation, differentiation and cytokine release. Platelet-neutrophil interactions boost oxidative burst, neutrophil extracellular trap formation and phagocytosis and play an important role in host defence. Platelet interactions with monocytes propagate their differentiation into macrophages, modulate cytokine release and attenuate macrophage functions. Depending on the underlying pathology, platelets can enhance or diminish leukocyte cytokine production, indicating that platelet-leukocyte interactions represent a fine balanced system to restrict excessive inflammation during infection. In atherosclerosis, platelet interaction with neutrophils, monocytes and dendritic cells accelerates key steps of atherogenesis by promoting leukocyte extravasation and foam cell formation. Platelet-leukocyte interactions at sites of atherosclerotic lesions destabilise atherosclerotic plaques and promote plaque rupture. Leukocytes in turn also modulate platelet function and production, which either results in enhanced platelet destruction or increased platelet production. This review aims to summarise the key effects of platelet-leukocyte interactions in inflammation, infection and atherosclerosis. PMID:27226790

  19. Bone scintigraphy in slipped capital femoral epiphysis

    SciTech Connect

    Gelfand, M.J.; Strife, J.L.; Graham, E.J.; Crawford, A.H.

    1983-12-01

    Tc-/sub 99m/ diphosphonate bone scans were performed on 11 children with slipped capital femoral epiphysis. On pinhole hip images, seven hips in seven patients had increased radionuclide uptake in the physis and adjacent proximal femoral metaphysis where the slip had occurred. Three hips in three patients had decreased radionuclide uptake in the femoral head on the side of the slipped epiphysis, indicating compromise of the femoral head blood supply. Three or more months following internal fixation, three children had scintigraphy that showed loss of the usual focal uptake in the physis and adjacent proximal femoral metaphysis. Bone scintigraphy in pediatric patients with slipped capital femoral epiphysis is valuable in defining the metabolic status of the femoral head. Absence of radiopharmaceutical uptake in the affected femoral head indicates that the femoral head is at risk for development of radiographic changes associated with aseptic necrosis.

  20. Adenosine thallium 201 myocardial perfusion scintigraphy

    SciTech Connect

    Verani, M.S. )

    1991-07-01

    Pharmacologic coronary vasodilation as an adjunct to myocardial perfusion imaging has become increasingly important in the evaluation of patients with coronary artery disease, in view of the large number of patients who cannot perform an adequate exercise test or in whom contraindications render exercise inappropriate. Adenosine is a very potent coronary vasodilator and when combined with thallium 201 scintigraphy produces images of high quality, with the added advantages of a very short half-life (less than 10 seconds) and the ability to adjust the dose during the infusion, which may enhance safety and curtail the duration of side effects. The reported sensitivity and specificity of adenosine thallium 201 scintigraphy for the detection of coronary artery disease are high and at least comparable with imaging after exercise or dipyridamole administration. 23 refs.

  1. Effects of irradiation on mandibular scintigraphy

    SciTech Connect

    Aitasalo, K.; Ruotsalainen, P.

    1985-11-01

    Technetium-99m methylene diphosphonate (Sn) scintigraphy with computer analysis was used to investigate alterations in the pathophysiology of the normal mandible and the pathologic mandible during and after irradiation. Slight but significant elevations of uptake levels were recorded as an early effect of irradiation. The elevations correlated with the duration of treatment and normalized over a follow-up period of 6 to 12 mo. Increased mandibular metabolism was found during irradiation and in osteomyelitis and osteoradionecrosis of the mandible. Scintigraphy with computer analysis proved a simple and valid method in the evaluation of early irradiation damage and pathophysiologic conditions of the mandible. The method can also be used to predict whether the irradiation damage will become irreversible.

  2. Role of scintigraphy in urinary tract infection

    SciTech Connect

    Conway, J.J.

    1988-10-01

    There is controversy regarding the role of radiological imaging for urinary tract infection (UTI). The gold standard has been the intravenous pyelogram (IVP). Yet, the IVP has a very limited value with only about 25% of children with pyelonephritis demonstrating abnormalities. Ultrasound (US) has recently been advocated as a replacement for the poorly sensitive and poorly specific IVP. However, comparative studies between US and IVP indicate only an equivalent sensitivity and specificity. Cortical scintigraphy with Technetium-99m glucoheptonate (99mTc GH) or 99mTc dimercaptosuccinic acid (99mTc DMSA) has also been advocated as a means of differentiating parenchymal (pyelonephritis) from nonparenchymal (lower UTI) involvement in UTI. The clinical presentation may be misleading especially in the infant and child in whom an elevated temperature, flank pain, shaking chills, or an elevated sedimentation rate are often lacking. The clinician attempts to localize the site of infection for it has a direct bearing upon the therapy. A collecting system infection can often be eradicated with a single oral dose of an appropriate antibiotic, whereas renal parenchymal involvement requires IV therapy for an extended interval. Cortical scintigraphy can localize the site of infection with a high degree of accuracy. Recent studies report a sensitivity of 86% and specificity of 81% of pyelonephritis. This is in contrast to the IVP with a sensitivity of only 24% and US with a sensitivity of only 42%. The scintigraphic appearance of parenchymal infection of the kidney is a spectrum of minimal to gross defects reflecting the degree of histologic involvement that spans from a mild infection to frank abscess. Cortical scintigraphy can be used to monitor the evolution of scarring following infection. Cortical scintigraphy with 99mTc DMSA or 99mTc GH is the method of choice for the initial evaluation of UTI. 37 references.

  3. Biliary atresia and neonatal hepatobiliary scintigraphy

    SciTech Connect

    Wynchank, S.; Guillet, J.; Leccia, F.; Soubiran, G.; Blanquet, P.

    1984-03-01

    Hepatobiliary scintigraphy using Tc-99m diethyl IDA was performed on 14 jaundiced neonates. It aided greatly the differential diagnosis between neonatal hepatitis and biliary atresia. Limitations in the interpretation of the results are described, as neonatal hepatitis may be accompanied by biliary excretion ranging from zero to normal. Also both biliary atresia (intra- and extrahepatic) and neonatal hepatitis may show no biliary excretion within 24 hours.

  4. Hormonal contraception and platelet function.

    PubMed

    Saleh, A A; Ginsburg, K A; Duchon, T A; Dorey, L G; Hirata, J; Alshameeri, R S; Dombrowski, M P; Mammen, E F

    1995-05-15

    73 healthy women (29 controls, 25 using OCs, and 19 using Norplant) were selected from the clinic population at North Oakland Medical Center for inclusion in this study after obtaining informed consent. Age, race, height, weight, blood pressure, and cigarette smoking were recorded for each subject. 12 patients were on monophasic OCs while 13 were on triphasic preparations. Both hormonal contraceptive groups had used their particular contraceptive for at least 3 months prior to blood drawing. Platelet tests were performed within 2 hours of sample collection: platelet counts (PLC) and mean platelet volume (MPV) were determined on an Automated Platelet Counter (Baker 810 Platelet Analyzer). Whole blood aggregation was performed on a platelet aggregometer (Chrono-Log, Model 550) using both ADP (ADP, 5 mM) and collagen (COLL, 2 mcg/ml) as inducing agents. Demographic differences were not significant (p 0.05) among the 3 treatment groups, whose average age was 25.3-25.8 years old. Furthermore, no significant differences (p 0.05) in platelet function were detected among controls or subjects receiving either oral contraceptives or Norplant, compared to control patients. The mean platelet counts (X 10/9/L) were 223 for OC users, 231 for Norplant users, and 232 for controls. The respective platelet aggregation (ADP, ohms) values were 12.5, 18.0, and 19.2 as well as (COLL, ohms) 35.6, 40.7, and 39.0. These results demonstrated that there is no evidence for altered platelet function, with the testing methods employed, in women using either Norplant or combination low dose oral contraceptives. To date, several studies have examined this issue, with contradictory reports about the effects of hormonal contraceptives in platelet function. After controlling for differences between various steroid preparations and other such confounding variables, some of these conflicting conclusions could be the result of a lack of uniformity among the methods used to evaluate platelet aggregation

  5. Bone scintigraphy in fluoride treated osteoporosis

    SciTech Connect

    Froelich, J.W.; Kleerekoper, M.; Parker, D.A.

    1985-05-01

    Quantitative bone scintigraphy was performed on 23 white females with post-menopausal osteoporosis and vertebral compression fractures. These patients were then entered into a randomized, double-blind clinical trial or sodium fluoride therapy (NaF=14, placebo=9) which included repeat bone scintigraphy every six months. Scintigraphic images were acquired for 500K counts per image over the total body with computer acquisition over the posterior thoracic and lumbar spine. Images were obtained on a wide field-of-view gamma camera two hours after injecting 15 mCi of Tc-99m MDP. Data analysis showed a significant reduction in the activity ratio of abnormal vertebral body to normal vertebral body in those patients treated with sodium fluoride (paired t-test p=0.0095). No significant change was observed in the control group of (p=0.142). These results suggest that sodium fluoride therapy promotes more rapid healing of osteoporotic vertebral fractures. They also demonstrate the utility of serial quantitative bone scintigraphy in assessing osteoporotic patients with vertebral compression fractures.

  6. In-111 WBC scintigraphy in adult osteomyelitis

    SciTech Connect

    Ehrlich, L.; Martin, R.H.; Saliken, J.

    1984-01-01

    Unlike pediatric bone infections, adult osteomyelitis is commonly related to trauma, surgery, or direct extension from an overlying soft tissue infection. Because of this, the findings on Tc-99m MDP bone scintigraphy tend to be nonspecific. Therefore the value of In-111 WBC scintigraphy in the diagnosis of adult osteomyelitis was evaluated. 52 scans were obtained on 51 adult patients who were consecutively referred to the authors' department with this provisional diagnosis. The diagnosis was confirmed by at least two of the following: positive culture, surgery, x-rays, laboratory results, and clinical response to antibiotics. Of the 52 scans studied the sensitivity was 84%, specificity was 82%, and the accuracy was 83%. False positive results occurred most frequently in patients with inflammatory arthritis. False negative examinations occurred in patients who had In-111 WBC concentration in overlying soft tissue obscuring the bony abnormality. Neither the chronicity of the infection, nor prior treatment with antibiotics created difficulty in scan interpretation. It was concluded that although somewhat less sensitive than TcMDP bone scanning, In-111 WBC scintigraphy is more specific than previously studied radiopharmaceuticals in the assessment of bone infections in the adult population.

  7. Glycans and the platelet life cycle.

    PubMed

    Li, Renhao; Hoffmeister, Karin M; Falet, Hervé

    2016-09-01

    Platelet numbers are intricately regulated to avoid spontaneous bleeding or arterial occlusion and organ damage. The growth factor thrombopoietin (TPO) drives platelet biogenesis by inducing megakaryocyte production. A recent study in mice identified a feedback mechanism by which clearance of aged, desialylated platelets stimulates TPO synthesis by hepatocytes. This new finding generated renewed interest in platelet clearance mechanisms. Here, different established and emerging mechanisms of platelet senescence and clearance will be reviewed with specific emphasis on the role of posttranslational modifications. PMID:27135356

  8. Myeloperoxidase induces the priming of platelets.

    PubMed

    Kolarova, H; Klinke, A; Kremserova, S; Adam, M; Pekarova, M; Baldus, S; Eiserich, J P; Kubala, L

    2013-08-01

    The release of myeloperoxidase (MPO) from polymorphonuclear neutrophils is a hallmark of vascular inflammation and contributes to the pathogenesis of vascular inflammatory processes. However, the effects of MPO on platelets as a contributory mechanism in vascular inflammatory diseases remain unknown. Thus, MPO interaction with platelets and its effects on platelet function were examined. First, dose-dependent binding of MPO (between 1.7 and 13.8nM) to both human and mouse platelets was observed. This was in direct contrast to the absence of MPO in megakaryocytes. MPO was localized both on the surface of and inside platelets. Cytoskeleton inhibition did not prevent MPO localization inside the three-dimensional platelet structure. MPO peroxidase activity was preserved upon the MPO binding to platelets. MPO sequestered in platelets catabolized NO, documented by the decreased production of NO (on average, an approximately 2-fold decrease). MPO treatment did not affect the viability of platelets during short incubations; however, it decreased platelet viability after long-term storage for 7 days (an approximately 2-fold decrease). The activation of platelets by MPO was documented by an MPO-mediated increase in the expression of surface platelet receptors P-selectin and PECAM-1 (of about 5 to 20%) and the increased formation of reactive oxygen species (of about 15 to 200%). However, the activation was only partial, as MPO did not induce the aggregation of platelets nor potentiate platelet response to classical activators. Nor did MPO induce a significant release of the content of granules. The activation of platelets by MPO was connected with increased MPO-treated platelet interaction with polymorphonuclear leukocytes (an approximately 1.2-fold increase) in vitro. In conclusion, it can be suggested that MPO can interact with and activate platelets, which can induce priming of platelets, rather than the classical robust activation of platelets. This can contribute to the

  9. Platelet function defects in chronic alcoholism.

    PubMed Central

    Mikhailidis, D P; Jenkins, W J; Barradas, M A; Jeremy, J Y; Dandona, P

    1986-01-01

    Platelet function in alcoholic patients was assessed on admission and during abstinence in hospital. On admission platelets from these patients were significantly less responsive (percentage aggregation and thromboxane A2 release) to conventional in vitro aggregating agents (adrenaline, adenosine diphosphate, and collagen) than platelets from healthy, moderate drinkers. Initially, platelet counts in platelet rich plasma tended to be low and the Simplate II bleeding times frequently prolonged. Platelet aggregation and thromboxane A2 release, however, were inhibited even in patients with normal platelet counts on admission. Platelet aggregation and thromboxane A2 release returned to normal or became hyper-responsive during two to three weeks of abstinence. Platelet counts rose during this period, the largest responses occurring in those patients with the lowest counts on admission. Bleeding times reverted to normal during abstinence and correlated significantly with changes in platelet aggregation, thromboxane A2 release, and platelet count and with the estimated ethanol consumption during the week before admission. Chronic, heavy alcohol ingestion evidently exerts an inhibitory effect on platelet function even in the absence of alcohol in the blood, and this phenomenon is reversible on abstaining. The impaired platelet function, together with the reduced platelet count, may contribute to the bleeding diathesis associated with chronic alcoholism and to the increased incidence and recurrence of gastrointestinal haemorrhage associated with excessive alcohol intake. PMID:3094624

  10. Evaluation of osseous metastasis in bone scintigraphy.

    PubMed

    Davila, Diego; Antoniou, Alexander; Chaudhry, Muhammad A

    2015-01-01

    Bone scintigraphy (BS) is an imaging tool commonly used for screening patients with cancer, especially those with high prevalence of osseous metastases including the breast, prostate, lung, thyroid, and kidney, which account for 80% of osseous metastasis. BS has been shown to be of value in the initial and subsequent treatment strategy of various malignancies. The purpose of this article is to evaluate the technical and imaging aspects of BS and to examine the present research into improved detection of osseous metastasis. PMID:25475375

  11. Dynamic light scattering can determine platelet function

    NASA Astrophysics Data System (ADS)

    Lee, Nathan

    2011-10-01

    Platelet transfusions are life-saving procedures for patients who are bleeding or undergoing chemotherapy. The effectiveness of transfusions depends on the number of platelets transfused and the platelet function. Platelet function correlates with proportion of discoid to activated platelets, morphology response to temperature stress, and inversely correlates with microparticle content. ThromboLUX is a novel device that determines platelet function by measuring all of these characteristics using dynamic light scattering (DLS). During periods of stress, such as decreased temperature, cytoskeletal rearrangements will cause normal, discoid platelets to activate and become spiny spheres. The formation of pseudopods of various lengths facilitates the clotting cascade and also increases the apparent size of platelets. ThromboLUX uses a 37-20-37 C temperature cycle that mimics the bleeding, storage, and transfusion process. As the temperature fluctuates, DLS will measure the changing platelet hydrodynamic radius and the size of any microparticles present. ThromboLUX analysis of platelet concentrates in vitro would allow determination of high platelet function units before transfusion and would therefore improve transfusion outcomes and patient safety. This study examined how DLS is able to distinguish between discoid and activated platelets as well as measure the parameters that contribute to high platelet function.

  12. Platelet function tests: a comparative review

    PubMed Central

    Paniccia, Rita; Priora, Raffaella; Alessandrello Liotta, Agatina; Abbate, Rosanna

    2015-01-01

    In physiological hemostasis a prompt recruitment of platelets on the vessel damage prevents the bleeding by the rapid formation of a platelet plug. Qualitative and/or quantitative platelet defects promote bleeding, whereas the high residual reactivity of platelets in patients on antiplatelet therapies moves forward thromboembolic complications. The biochemical mechanisms of the different phases of platelet activation – adhesion, shape change, release reaction, and aggregation – have been well delineated, whereas their complete translation into laboratory assays has not been so fulfilled. Laboratory tests of platelet function, such as bleeding time, light transmission platelet aggregation, lumiaggregometry, impedance aggregometry on whole blood, and platelet activation investigated by flow cytometry, are traditionally utilized for diagnosing hemostatic disorders and managing patients with platelet and hemostatic defects, but their use is still limited to specialized laboratories. To date, a point-of-care testing (POCT) dedicated to platelet function, using pertinent devices much simpler to use, has now become available (ie, PFA-100, VerifyNow System, Multiplate Electrode Aggregometry [MEA]). POCT includes new methodologies which may be used in critical clinical settings and also in general laboratories because they are rapid and easy to use, employing whole blood without the necessity of sample processing. Actually, these different platelet methodologies for the evaluation of inherited and acquired bleeding disorders and/or for monitoring antiplatelet therapies are spreading and the study of platelet function is strengthening. In this review, well-tried and innovative platelet function tests and their methodological features and clinical applications are considered. PMID:25733843

  13. Genetics Home Reference: gray platelet syndrome

    MedlinePlus

    ... to play a role in the formation of alpha-granules, which are sacs inside platelets that contain ... injury that causes bleeding, the proteins stored in alpha-granules help platelets stick to one another to ...

  14. [Assessment of platelet function in man].

    PubMed

    Gaussem, Pascale

    2006-01-01

    Assessment of platelet function was primarily designed to explore patients with hemostatic disorders, but is becoming important for the monitoring of anti platelet agents, mostly aspirin and clopidogrel. Beside platelet counting, morphological analysis and bleeding time, a number of dedicated platelet function instruments are now available, generally allowing a rapid evaluation of platelet function in whole blood. The other tests including aggregometry and ELISA measurement of activation markers are generally restricted to specialized laboratories. Although aggregometry is still considered as the "gold standard", the recently developed flow cytometric-based platelet function analysis provides a wide choice of tests that assess the number of surface receptors, the measure of secretion and aggregation, the quantification of microparticules and leukocyte-platelet aggregates. It also allows the measure of the function of the ADP receptor P2Y12 by the phosphorylation level of the VASP protein, method currently under evaluation to monitor the platelet response to clopidogrel treatment. PMID:17243268

  15. Effect of photodynamic therapy on mouse platelets

    NASA Astrophysics Data System (ADS)

    Zhou, Chuannong; Chi, Shunji; Deng, Jinsheng; Zhang, Hua; Liang, Junlin; Ha, Xian-wen

    1993-06-01

    Normal mice received hematoporphyrin derivative (HpD) i.v. prior to red light irradiation and the platelet-rich plasma was prepared and irradiated by red light. The platelets were processed for EM examination and stereological analysis. It was shown the 16 hrs after irradiation almost all platelets were necrotized; 8 hours after irradiation about one fourth of the platelets were necrotized and the remaining were considerably damaged. Immediately after irradiation a small number of platelets became necrotic and most other platelets were swollen and deformated, showing significantly increased mean area, perimeter and short axis, and mean cell volume and cell surface area. The findings indicate that platelets are highly sensitive to PDT action and can be directly and rapidly damaged by PDT even in the absence of vascular endothelial cells. The early platelet photoactivation may play an important role in the initiation of early vascular damage and microcirculatory alterations induced by PDT in vivo.

  16. CD8+ T cells induce platelet clearance in the liver via platelet desialylation in immune thrombocytopenia

    PubMed Central

    Qiu, Jihua; Liu, Xuena; Li, Xiaoqing; Zhang, Xu; Han, Panpan; Zhou, Hai; Shao, Linlin; Hou, Yu; Min, Yanan; Kong, Zhangyuan; Wang, Yawen; Wei, Yu; Liu, Xinguang; Ni, Heyu; Peng, Jun; Hou, Ming

    2016-01-01

    In addition to antiplatelet autoantibodies, CD8+ cytotoxic T lymphocytes (CTLs) play an important role in the increased platelet destruction in immune thrombocytopenia (ITP). Recent studies have highlighted that platelet desialylation leads to platelet clearance via hepatocyte asialoglycoprotein receptors (ASGPRs). Whether CD8+ T cells induce platelet desialylation in ITP remains unclear. Here, we investigated the cytotoxicity of CD8+ T cells towards platelets and platelet desialylation in ITP. We found that the desialylation of fresh platelets was significantly higher in ITP patients with positive cytotoxicity of CD8+ T cells than those without cytotoxicity and controls. In vitro, CD8+ T cells from ITP patients with positive cytotoxicity induced significant platelet desialylation, neuraminidase-1 expression on the platelet surface, and platelet phagocytosis by hepatocytes. To study platelet survival and clearance in vivo, CD61 knockout mice were immunized and their CD8+ splenocytes were used. Platelets co-cultured with these CD8+ splenocytes demonstrated decreased survival in the circulation and increased phagocytosis in the liver. Both neuraminidase inhibitor and ASGPRs competitor significantly improved platelet survival and abrogated platelet clearance caused by CD8+ splenocytes. These findings suggest that CD8+ T cells induce platelet desialylation and platelet clearance in the liver in ITP, which may be a novel mechanism of ITP. PMID:27321376

  17. CD8(+) T cells induce platelet clearance in the liver via platelet desialylation in immune thrombocytopenia.

    PubMed

    Qiu, Jihua; Liu, Xuena; Li, Xiaoqing; Zhang, Xu; Han, Panpan; Zhou, Hai; Shao, Linlin; Hou, Yu; Min, Yanan; Kong, Zhangyuan; Wang, Yawen; Wei, Yu; Liu, Xinguang; Ni, Heyu; Peng, Jun; Hou, Ming

    2016-01-01

    In addition to antiplatelet autoantibodies, CD8(+) cytotoxic T lymphocytes (CTLs) play an important role in the increased platelet destruction in immune thrombocytopenia (ITP). Recent studies have highlighted that platelet desialylation leads to platelet clearance via hepatocyte asialoglycoprotein receptors (ASGPRs). Whether CD8(+) T cells induce platelet desialylation in ITP remains unclear. Here, we investigated the cytotoxicity of CD8(+) T cells towards platelets and platelet desialylation in ITP. We found that the desialylation of fresh platelets was significantly higher in ITP patients with positive cytotoxicity of CD8(+) T cells than those without cytotoxicity and controls. In vitro, CD8(+) T cells from ITP patients with positive cytotoxicity induced significant platelet desialylation, neuraminidase-1 expression on the platelet surface, and platelet phagocytosis by hepatocytes. To study platelet survival and clearance in vivo, CD61 knockout mice were immunized and their CD8(+) splenocytes were used. Platelets co-cultured with these CD8(+) splenocytes demonstrated decreased survival in the circulation and increased phagocytosis in the liver. Both neuraminidase inhibitor and ASGPRs competitor significantly improved platelet survival and abrogated platelet clearance caused by CD8(+) splenocytes. These findings suggest that CD8(+) T cells induce platelet desialylation and platelet clearance in the liver in ITP, which may be a novel mechanism of ITP. PMID:27321376

  18. New treatment for low platelets.

    PubMed

    Grodeck, B

    1995-01-01

    The Food and Drug Administration (FDA) recently approved WinRho SD, a new treatment for immune thrombocytopenic purpura (ITP). A clinical trial in children with acute ITP found that WinRho SD is as effective as IVIG or prednisone, but less expensive and dramatically easier to administer. WinRho SD is the first polyclonal antibody product shown to increase platelets in ITP patients. Platelets usually rise within one to two days and peak within seven to fourteen days after initial therapy. On average, platelet levels are maintained for approximately thirty days. Each year, 50,000 people nationally suffer from ITP as a complication of HIV infection, while another 18,000 manifest the disease as a primary condition. PMID:11362579

  19. Hepatobiliary scintigraphy in a patient with bilhemia.

    PubMed

    François, D; Walrand, S; Van Nieuwenhuyse, J P; de Ville de Goyet, J; Pauwels, S

    1994-09-01

    A 4-year-old child referred for acute jaundice following percutaneous needle biopsy of the liver underwent hepatobiliary scintigraphy. Although all conventional liver tests suggested preservation of hepatocyte function, the tracer uptake in the liver appeared dramatically reduced at scintigraphy and the blood pool activity did not decrease significantly until the end of the study. Visualization of the bile ducts indicated, however, that the tracer was taken up by the hepatocyte and further excreted into the biliary tree. There was no tracer pooling in the biliary tree although no bowel activity was observed, even on delayed images. The association of persistent blood pool activity, bile duct visualization without tracer pooling, and nonvisualization of the bowel was caused by a continuous recirculation of the tracer from the biliary tree into the bloodstream. The presence of a biliovenous fistula was further proven by percutaneous transhepatic cholangiography performed 24 h later. Since 1975, only 16 cases of bilhemia have been reported. To the best of our knowledge the scintigraphic pattern of this rare but life-threatening complication has not previously been reported. PMID:7995281

  20. Megakaryocyte rupture for acute platelet needs

    PubMed Central

    Stritt, Simon

    2015-01-01

    Circulating platelets were thought to arise solely from the protrusion and fragmentation of megakaryocyte cytoplasm. Now, Nishimura et al. (2015. J. Cell Biol. http://dx.doi.org/10.1083/jcb.201410052) show that platelet release from megakaryocytes can be induced by interleukin-1α (IL-1α) via a new rupture mechanism, which yields higher platelet numbers, occurs independently of the key regulator of megakaryopoiesis thrombopoietin, and may occur during situations of acute platelet need. PMID:25963815

  1. Megakaryocyte rupture for acute platelet needs.

    PubMed

    Nieswandt, Bernhard; Stritt, Simon

    2015-05-11

    Circulating platelets were thought to arise solely from the protrusion and fragmentation of megakaryocyte cytoplasm. Now, Nishimura et al. (2015. J. Cell Biol. http://dx.doi.org/10.1083/jcb.201410052) show that platelet release from megakaryocytes can be induced by interleukin-1α (IL-1α) via a new rupture mechanism, which yields higher platelet numbers, occurs independently of the key regulator of megakaryopoiesis thrombopoietin, and may occur during situations of acute platelet need. PMID:25963815

  2. Platelet Activation: The Mechanisms and Potential Biomarkers

    PubMed Central

    Yun, Seong-Hoon; Sim, Eun-Hye; Goh, Ri-Young; Park, Joo-In

    2016-01-01

    Beyond hemostasis and thrombosis, an increasing number of studies indicate that platelets play an integral role in intercellular communication, mediating inflammatory and immunomodulatory activities. Our knowledge about how platelets modulate inflammatory and immunity has greatly improved in recent years. In this review, we discuss recent advances in the pathways of platelet activation and potential application of platelet activation biomarkers to diagnosis and prediction of disease states. PMID:27403440

  3. Antiplatelet drugs in patients with enhanced platelet turnover: biomarkers versus platelet function testing.

    PubMed

    Freynhofer, Matthias K; Gruber, Susanne C; Grove, Erik L; Weiss, Thomas W; Wojta, Johann; Huber, Kurt

    2015-08-31

    Platelets are key players in atherothrombosis. Antiplatelet therapy comprising aspirin alone or with P2Y12-inhibitors are effective for prevention of atherothrombotic complications. However, there is interindividual variability in the response to antiplatelet drugs, leaving some patients at increased risk of recurrent atherothrombotic events. Several risk factors associated with high on-treatment platelet reactivity (HTPR), including elevated platelet turnover, have been identified. Platelet turnover is adequately estimated from the fraction of reticulated platelets. Reticulated platelets are young platelets, characterised by residual messenger RNA. They are larger, haemostatically more active and there is evidence that platelet turnover is a causal and prognostic factor in atherothrombotic disease. Whether platelet turnover per se represents a key factor in pathogenesis, progression and prognosis of atherothrombotic diseases (with focus on acute coronary syndromes) or whether it merely facilitates insufficient platelet inhibition will be discussed in this state-of-the art review. PMID:26272640

  4. Multiscale model of platelet translocation and collision

    NASA Astrophysics Data System (ADS)

    Wang, Weiwei; Mody, Nipa A.; King, Michael R.

    2013-07-01

    The tethering of platelets on the injured vessel surface mediated by glycoprotein Ibα (GPIbα) - Von Willebrand factor (vWF) bonds, as well as the interaction between flowing platelets and adherent platelets, are two key events that take place immediately following blood vessel injury. This early-stage platelet deposition and accumulation triggers the initiation of hemostasis, a self-defensive mechanism to prevent the body from excessive blood loss. To understand and predict this complex process, one must integrate experimentally determined information on the mechanics and biochemical kinetics of participating receptors over very small time frames (1-1000 μs) and length scales (10-100 nm), to collective phenomena occurring over seconds and tens of microns. In the present study, a unique three dimensional multiscale computational model, Platelet Adhesive Dynamics (PAD), was applied to elucidate the unique physics of (i) a non-spherical, disk-shaped platelet interacting and tethering onto the damaged vessel wall followed by (ii) collisional interactions between a flowing platelet with a downstream adherent platelet. By analyzing numerous simulations under different physiological conditions, we conclude that the platelet's unique spheroid-shape provides heterogeneous, orientation-dependent translocation (rolling) behavior which enhances cell-wall interactions. We also conclude that platelet-platelet near field interactions are critical for cell-cell communication during the initiation of microthrombi. The PAD model described here helps to identify the physical factors that control the initial stages of platelet capture during this process.

  5. New Horizons in Platelets Flow Cytometry

    PubMed Central

    Saboor, Muhammad; Moinuddin, Moinuddin; Ilyas, Samina

    2013-01-01

    Platelet flow cytometry is an emerging tool in diagnostic and therapeutic hematology. It is eminently suited to study the expression of platelet surface receptors both qualitatively as well as quantitatively. It can serve as a useful marker for the documentation of in vivo platelet activation, and thus, fore-warn the risk of thromboembolism in patients with diabetes mellitus, coronary syndromes, peripheral vascular diseases, and pre-eclampsia. This technique can also be extended to study and compare the effect of various antiplatelet drugs on the level of activation of platelets and to establish any dose-effect relationship of these drugs. Topographical localization of platelet granules and study of platelet-platelet and platelet-leukocyte interaction is also possible by this procedure. All these parameters serve as pointers towards the presence of activated platelets in the circulation with its thromboembolic consequences. This is a simple reliable and cost effective technique which has a wide application in the diagnosis of various inherited and acquired platelet disorders. Study of platelet cluster of differentiation (CD) markers in various inherited disorders i.e. Bernard Soulier’s disease, von Willebrand disease, Glanzman’s disease, and Grey platelet syndrome may help categories the molecular lesions in these oft under-studied disorders. PMID:23983579

  6. Exploratory studies of extended storage of apheresis platelets in a platelet additive solution (PAS).

    PubMed

    Slichter, Sherrill J; Corson, Jill; Jones, Mary Kay; Christoffel, Todd; Pellham, Esther; Bailey, S Lawrence; Bolgiano, Doug

    2014-01-01

    To evaluate the poststorage viability of apheresis platelets stored for up to 18 days in 80% platelet additive solution (PAS)/20% plasma, 117 healthy subjects donated platelets using the Haemonetics MCS+, COBE Spectra (Spectra), or Trima Accel (Trima) systems. Control platelets from the same subjects were compared with their stored test PAS platelets by radiolabeling their stored and control platelets with either (51)chromium or (111)indium. Trima platelets met Food and Drug Administration poststorage platelet viability criteria for only 7 days vs almost 13 days for Haemonetics platelets; ie, platelet recoveries after these storage times averaged 44 ± 3% vs 49 ± 3% and survivals were 5.4 ± 0.3 vs 4.6 ± 0.3 days, respectively. The differences in storage duration are likely related to both the collection system and the storage bag. The Spectra and Trima platelets were hyperconcentrated during collection, and PAS was added, whereas the Haemonetics platelets were elutriated with PAS, which may have resulted in less collection injury. When Spectra and Trima platelets were stored in Haemonetics' bags, poststorage viability was significantly improved. Platelet viability is better maintained in vitro than in vivo, allowing substantial increases in platelet storage times. However, implementation will require resolution of potential bacterial overgrowth during storage. PMID:24258816

  7. Thallium-201 scintigraphy in differentiated thyroid cancer: Comparison with radioiodine scintigraphy and serum thyroglobulin determinations

    SciTech Connect

    Ramanna, L.; Waxman, A.; Braunstein, G. )

    1991-03-01

    The role of thallium-201 ({sup 201}TI) scintigraphy in the follow-up evaluation of differentiated thyroid carcinoma (DTC) is controversial. Desirable characteristics of {sup 201}TI scintigraphy including the potential for no thyroid hormone withdrawal, immediate imaging postinjection, and low radiation burden relative to iodine-131 ({sup 131}I) suggests it is logistically superior to {sup 131}I scintigraphy. Fifty-two patients with DTC were evaluated with {sup 201}TI and {sup 131}I neck and chest images, and serum thyroglobulin measurements. In post-thyroidectomy and pre-{sup 131}I ablation therapy patients, very little {sup 201}TI accumulation was noted within the thyroid bed, with discordantly increased {sup 131}I activity and normal serum thyroglobulin measurements. Twenty-nine percent of patients evaluated after {sup 131}I ablative therapy had elevated serum thyroglobulin levels and localized neck and chest abnormalities on 201TI scan that were not seen on {sup 131}I studies. Our data suggest that {sup 201}TI is more sensitive than {sup 131}I diagnostic (5 mCi) studies for detection of DTC, while {sup 131}I is more sensitive in detecting normal residual thyroid tissue postoperatively.

  8. Mechanisms of platelet-mediated liver regeneration.

    PubMed

    Lisman, Ton; Porte, Robert J

    2016-08-01

    Platelets have multiple functions beyond their roles in thrombosis and hemostasis. Platelets support liver regeneration, which is required after partial hepatectomy and acute or chronic liver injury. Although it is widely assumed that platelets stimulate liver regeneration by local excretion of mitogens stored within platelet granules, definitive evidence for this is lacking, and alternative mechanisms deserve consideration. In-depth knowledge of mechanisms of platelet-mediated liver regeneration may lead to new therapeutic strategies to treat patients with failing regenerative responses. PMID:27297793

  9. Splenic release of platelets contributes to increased circulating platelet size and inflammation after myocardial infarction.

    PubMed

    Gao, Xiao-Ming; Moore, Xiao-Lei; Liu, Yang; Wang, Xin-Yu; Han, Li-Ping; Su, Yidan; Tsai, Alan; Xu, Qi; Zhang, Ming; Lambert, Gavin W; Kiriazis, Helen; Gao, Wei; Dart, Anthony M; Du, Xiao-Jun

    2016-07-01

    Acute myocardial infarction (AMI) is characterized by a rapid increase in circulating platelet size but the mechanism for this is unclear. Large platelets are hyperactive and associated with adverse clinical outcomes. We determined mean platelet volume (MPV) and platelet-monocyte conjugation (PMC) using blood samples from patients, and blood and the spleen from mice with AMI. We further measured changes in platelet size, PMC, cardiac and splenic contents of platelets and leucocyte infiltration into the mouse heart. In AMI patients, circulating MPV and PMC increased at 1-3 h post-MI and MPV returned to reference levels within 24 h after admission. In mice with MI, increases in platelet size and PMC became evident within 12 h and were sustained up to 72 h. Splenic platelets are bigger than circulating platelets in normal or infarct mice. At 24 h post-MI, splenic platelet storage was halved whereas cardiac platelets increased by 4-fold. Splenectomy attenuated all changes observed in the blood, reduced leucocyte and platelet accumulation in the infarct myocardium, limited infarct size and alleviated cardiac dilatation and dysfunction. AMI-induced elevated circulating levels of adenosine diphosphate and catecholamines in both human and the mouse, which may trigger splenic platelet release. Pharmacological inhibition of angiotensin-converting enzyme, β1-adrenergic receptor or platelet P2Y12 receptor reduced platelet abundance in the murine infarct myocardium albeit having diverse effects on platelet size and PMC. In conclusion, AMI evokes release of splenic platelets, which contributes to the increase in platelet size and PMC and facilitates myocardial accumulation of platelets and leucocytes, thereby promoting post-infarct inflammation. PMID:27129192

  10. Evidence that platelet buoyant density, but not size, correlates with platelet age in man

    SciTech Connect

    Mezzano, D.; Hwang, K.; Catalano, P.; Aster, R.H.

    1981-01-01

    Following infusion of 51Cr-labeled autologous platelets into normal subjects, high-density (HD) and low-density (LD) platelet cohorts were isolated by prolonged centrifugation in isosmotic arabino-galactan (Stractan). Specific radio-activity of LD platelets declined rapidly post-infusion (T1/2 . 1.5 days), but specific radioactivity of HD platelets remained constant or increased over a 3--4-day period and gradually declined for 6--7 days thereafter. These differences were exaggerated when platelet cohorts enriched in LD or HD cells by slow centrifugation in high-density albumin were labeled and transfused. Mean survival of a platelet cohort enriched with HD cells was significantly (P less than 0.02) shorter (7.73 days) than that of a cohort enriched with LD cells (9.33) days). In normal subjects treated with aspirin, capacity for thromboxane synthesis was regained more rapidly (P less than 0.05) in LD than in HD platelets. HD and LD platelets differed only slightly in mean volume (HD platelets . 7.57 mu3, LD platelets . 6.87 mu3, 0.05 less than P less than 0.01). We believe the most logical interpretation of these findings is that under normal conditions in man, newly formed platelets are less dense on the average than total platelets and become more dense as they age in the circulation. Thus, specific radioactivity of LD platelets declines rapidly as these platelets move into a more dense compartment and are replaced by newly formed, unlabelled cells; specific radioactivity of HD platelets remains constant or increases as labelled platelets enter this compartment in numbers equal to or greater than the number leaving it at the end of their life span. The similarity in mean volumes of LD and HD platelets suggests that platelet size is unrelated to platelet age under normal conditions.

  11. Signaling during platelet adhesion and activation

    PubMed Central

    Li, Zhenyu; Delaney, M. Keegan; O’Brien, Kelly A.; Du, Xiaoping

    2011-01-01

    Upon vascular injury, platelets are activated by adhesion to adhesive proteins like von Willebrand factor and collagen, or by soluble platelet agonists like ADP, thrombin, and thromboxane A2. These adhesive proteins and soluble agonists induce signal transduction via their respective receptors. The various receptor-specific platelet activation signaling pathways converge into common signaling events, which stimulate platelet shape change, granule secretion, and ultimately induce the “inside-out” signaling process leading to activation of the ligand binding function of integrin αIIbβ3. Ligand binding to integrin αIIbβ3 mediates platelet adhesion and aggregation and triggers “outside-in” signaling, resulting in platelet spreading, additional granule secretion, stabilization of platelet adhesion and aggregation, and clot retraction. It has become increasingly evident that agonist-induced platelet activation signals also crosstalk with integrin “outside-in” signals to regulate platelet responses. Platelet activation involves a series of rapid positive feedback loops that greatly amplify initial activation signals, and enable robust platelet recruitment and thrombus stabilization. Recent studies have provided novel insight into the molecular mechanisms of these processes. PMID:21071698

  12. Numerical simulation of platelet margination in microcirculation

    NASA Astrophysics Data System (ADS)

    Zhao, Hong; Shaqfeh, Eric

    2009-11-01

    The adhesion of platelets to vascular walls is the first step in clotting. This process critically depends on the preferential concentration of platelets near walls. The presence of red blood cells, which are the predominant blood constituents, is known to affect the steady state platelet concentration and the dynamic platelet margination, but the underlying mechanism is not well understood to-day. We use a direct numerical simulation to study the platelet margination process, with particular emphasis on the Stokesian hydrodynamic interactions among red cells, platelets, and vessel walls. Well-known mechanical models are used for the shearing and bending stiffness of red cell membranes, and the stiffer platelets are modeled as rigid discoids. A boundary integral formulation is used to solve the flow field, where the numerical solution procedure is accelerated by a parallel O(N N) smooth particle-mesh Ewald method. The effects of red cell hematocrit and deformability will be discussed.

  13. Manipulating megakaryocytes to manufacture platelets ex vivo

    PubMed Central

    Karagiannis, P; Eto, K

    2015-01-01

    Historically, platelet transfusion has proven a reliable way to treat patients suffering from thrombocytopenia or similar ailments. An undersupply of donors, however, has demanded alternative platelet sources. Scientists have therefore sought to recapitulate the biological events that convert hematopoietic stem cells into platelets in the laboratory. Such platelets have shown good function and potential for treatment. Yet the number manufactured ex vivo falls well short of clinical application. Part of the reason is the remarkable gaps in our understanding of the molecular mechanisms driving platelet formation. Using several stem cell sources, scientists have progressively clarified the chemical signaling and physical microenvironment that optimize ex vivo platelets and reconstituted them in synthetic environments. Key advances in cell reprogramming and the ability to propagate self-renewal have extended the lifetime of megakaryocytes to increase the pool of platelet progenitors. PMID:26149050

  14. Role of platelets in allergic airway inflammation.

    PubMed

    Idzko, Marco; Pitchford, Simon; Page, Clive

    2015-06-01

    Increasing evidence suggests an important role for platelets and their products (e.g., platelet factor 4, β-thromboglobulin, RANTES, thromboxane, or serotonin) in the pathogenesis of allergic diseases. A variety of changes in platelet function have been observed in patients with asthma, such as alterations in platelet secretion, expression of surface molecules, aggregation, and adhesion. Moreover, platelets have been found to actively contribute to most of the characteristic features of asthma, including bronchial hyperresponsiveness, bronchoconstriction, airway inflammation, and airway remodeling. This review brings together the current available data from both experimental and clinical studies that have investigated the role of platelets in allergic airway inflammation and asthma. It is anticipated that a better understanding of the role of platelets in the pathogenesis of asthma might lead to novel promising therapeutic approaches in the treatment of allergic airway diseases. PMID:26051948

  15. [The equation for platelet aggregation rate].

    PubMed

    Vrzheshch, P V; Verkhusha, V V; Varfolomeev, S D

    1990-01-01

    A platelet aggregation model in shear flow taking into account the kinetics of intercellular fibrinogen bond formation limited by aggregated platelets rotation time was considered. For this consideration the average duration of platelets interaction in flow with shear rate value G is shown to be pi/4G. One fibrinogen bond is sufficient to form a solid aggregate between two platelets. The equation for single platelets disappearance rate concerned with intercellular fibrinogen bond formation, stochastic character of bond distribution in collided platelets and hydrodynamically controlled interaction time was obtained. The Hill's approximation for the obtained aggregation rate dependences was suggested and appropriate constants were determined. The qualitative criterion of platelets aggregating systems behavior was introduced. PMID:2245229

  16. Quantitative planar imaging in renal scintigraphy

    NASA Astrophysics Data System (ADS)

    Lárraga, J. M.; Martínez-Dávalos, A.; Martínez-Duncker, C.; Rodríguez, R. Herrera

    2002-08-01

    In this work we show the results of the implementation of the double energy window method (DEW) to correct for scatter and geometric mean of opposite image to correct for attenuation of radiation within the patient for absolute quantification of radiotracer in renal scintigraphy studies. We show that DEW method subestimates the scatter radiation within main energy window and that result in a 11% of maximun error for the determination of true activity of a renal kidney phantom. Moreover, in order to avoid transmission scans of patients we perform a Monte Carlo simulation (MC) for the determination of scatter component of the main energy window. The results of the MC simulation was validated with experimental data of emission studies.

  17. Useful hepatic parenchymal imaging in hepatobiliary scintigraphy

    SciTech Connect

    Brown, M.L.; Freitas, J.E.; Wahner, H.W.

    1981-05-01

    Hepatobiliary scintigraphy with the /sup 99m/Tc-labeled iminodiacetic acid derivatives has been shown to be useful in the evaluation of biliary tract diseases, especially for the diagnosis of acute cholecystitis. Little emphasis has been placed on the importance of the hepatic parenchymal image that occurs early in the imaging sequence. To determine what information can be obtained from the hepatic parenchymal image, a comparison was carried out of sulfur colloid and iminodiacetic acid images in 50 patients with focal defects. In 46 of 50 patients, the number and position of lesions on the two studies were similar, while in four patients the images were discordant. In addition to being very similar in lesion detection, the iminodiacetic acid scans also allowed more specificity in the later imaging (biliary phase) in 13 cases.

  18. Mean platelet volume as an indicator of platelet rejuvenation following bone-marrow transplantation. Master's thesis

    SciTech Connect

    Seanger, D.G.

    1986-07-01

    Thrombocytopenia of unpredictable duration and severity is an expected outcome of the radiation/chemotherapy protocols performed prior to bone-marrow transplantation. Serial evaluation of the platelet count and mean platelet volume of patients diagnosed with acute leukemia demonstrated the mean platelet volume to increase into reference limits 24 to 40 hours prior to a rise in the platelet count in those patients whose bone-marrow successfully responded to induction chemotherapy. Serial platelet counts and measurements of mean platelet volume were performed on 31 patients following bone marrow transplantation. Numerous platelet transfusions, together with sustained thrombocytopenia, inhibited accurate assessment of 29 of 31 patients. Two patients, however, demonstrated a rise in the mean platelet volume prior to an increase in the platelet count. Both of these patients received no platelet transfusions during the period preceding or following the rise in the platelet count. It was proposed that the serial evaluation of the mean platelet volume may assist practitioners in the decision-making process of deciding whether platlet transfusions are required, or an increase in the number of circulating platelets is imminent. A decision not to transfuse would have the direct benefit of decreasing patient costs, in conjunction with eliminating a potential source for the development of an antibody against platelets.

  19. Gallium 67 scintigraphy in glomerular disease

    SciTech Connect

    Bakir, A.A.; Lopez-Majano, V.; Levy, P.S.; Rhee, H.L.; Dunea, G.

    1988-12-01

    To evaluate the diagnostic usefulness of gallium 67 scintigraphy in glomerular disease, 45 patients with various glomerulopathies, excluding lupus nephritis and renal vasculitis, were studied. Persistent renal visualization 48 hours after the gallium injection, a positive scintigram, was graded as + (less than), ++ (equal to), and +++ (greater than) the hepatic uptake. Positive scintigrams were seen in ten of 16 cases of focal segmental glomerulosclerosis, six of 11 cases of proliferative glomerulonephritis, and one case of minimal change, and one of two cases of membranous nephropathy; also in three of six cases of sickle glomerulopathy, two cases of diabetic neuropathy, one of two cases of amyloidosis, and one case of mild chronic allograft rejection. The 25 patients with positive scans were younger than the 20 with negative scans (31 +/- 12 v 42 +/- 17 years; P less than 0.01), and exhibited greater proteinuria (8.19 +/- 7.96 v 2.9 +/- 2.3 S/d; P less than 0.01) and lower serum creatinine values (2 +/- 2 v 4.1 +/- 2.8 mg/dL; P less than 0.01). The amount of proteinuria correlated directly with the intensity grade of the gallium image (P less than 0.02), but there was no correlation between the biopsy diagnosis and the outcome of the gallium scan. It was concluded that gallium scintigraphy is not useful in the differential diagnosis of the glomerular diseases under discussion. Younger patients with good renal function and heavy proteinuria are likely to have a positive renal scintigram regardless of the underlying glomerulopathy.

  20. Platelet Function Tests in Bleeding Disorders.

    PubMed

    Lassila, Riitta

    2016-04-01

    Functional disorders of platelets can involve any aspect of platelet physiology, with many different effects or outcomes. These include platelet numbers (thrombocytosis or thrombocytopenia); changes in platelet production or destruction, or capture to the liver (Ashwell receptor); altered adhesion to vascular injury sites and/or influence on hemostasis and wound healing; and altered activation or receptor functions, shape change, spreading and release reactions, procoagulant and antifibrinolytic activity. Procoagulant membrane alterations, and generation of thrombin and fibrin, also affect platelet aggregation. The above parameters can all be studied, but standardization and quality control of assay methods have been limited despite several efforts. Only after a comprehensive clinical bleeding assessment, including family history, information on drug use affecting platelets, and exclusion of coagulation factor, and tissue deficits, should platelet function testing be undertaken to confirm an abnormality. Current diagnostic tools include blood cell counts, platelet characteristics according to the cell counter parameters, peripheral blood smear, exclusion of pseudothrombocytopenia, whole blood aggregometry (WBA) or light transmission aggregometry (LTA) in platelet-rich plasma, luminescence, platelet function analysis (PFA-100) for platelet adhesion and deposition to collagen cartridges under blood flow, and finally transmission electron microscopy to exclude rare structural defects leading to functional deficits. The most validated test panels are included in WBA, LTA, and PFA. Because platelets are isolated from their natural environment, many simplifications occur, as circulating blood and interaction with vascular wall are omitted in these assays. The target to reach a highly specific platelet disorder diagnosis in routine clinical management can be exhaustive, unless needed for genetic counseling. The elective overall assessment of platelet function disorder

  1. Membrane Changes Associated with Platelet Activation

    PubMed Central

    George, James N.; Lyons, Roger M.; Morgan, Rebecca K.

    1980-01-01

    The effect of aggregation and secretion on membrane proteins was studied in washed human platelets. Reversible aggregation without secretion was stimulated by ADP and secretion without aggregation was stimulated by thrombin in the presence of EDTA. No loss of platelet surface glycoproteins occurred during reversible ADP-induced platelet aggregation, as measured by quantitative polyacrylamide gel electrophoresis analysis of platelets that were labeled with 125I-diazotized diiodosulfanilic acid (DD125ISA) before ADP stimulation. Also, no new proteins became exposed on the platelet surface after ADP aggregation, as determined by DD125ISA labeling after stimulation. Thrombin-induced platelet secretion also caused no loss of platelet surface glycoproteins. However, after platelet secretion two new proteins were labeled by DD125ISA: (a) actin and (b) the 149,000-mol wt glycoprotein (termed GP-G), which is contained in platelet granules and secreted in response to thrombin. The identity of DD125ISA-labeled actin was confirmed by four criteria: (a) comigration with actin in three different sodium dodecyl sulfate-polyacrylamide gel electrophoresis systems, (b) elution from a particulate fraction in low ionic strength buffer, (c) co-migration with actin in isoelectric focusing, and (d) binding to DNase I. The identity of actin and its appearance on the platelet surface after thrombin-induced secretion was also demonstrated by the greater binding of an anti-actin antibody to thrombin-treated platelets, measured with 125I-staphylococcal protein A. Therefore, major platelet membrane changes occur after secretion but not after reversible aggregation. The platelet surface changes occurring with secretion may be important in the formation of irreversible platelet aggregates and in the final retraction of the blood clot. Images PMID:6772667

  2. In-111-labeled leukocyte scintigraphy in suspected orthopedic prosthesis infection: comparison with other imaging modalities

    SciTech Connect

    Magnuson, J.E.; Brown, M.L.; Hauser, M.F.; Berquist, T.H.; Fitzgerald, R.H. Jr.; Klee, G.G.

    1988-07-01

    When infection of prosthetic orthopedic implants is suspected, optimal management requires accurate confirmation or exclusion of infection. The authors retrospectively studied 98 patients with possible infection who underwent scanning with indium-111-labeled white blood cells (WBCs) and subsequently underwent surgery within 14 days. At surgery, 50 patients had infections, as determined by means of culture or histologic results. The diagnostic accuracy of In-111 scanning was compared with that of plain radiography, arthrography, three-phase bone scanning, and various clinical and laboratory findings classically associated with infection. Positive findings on In-111 WBC scans and elevated erythrocyte sedimentation rates were found to be the most predictive variables in the diagnosis of septic prostheses (P less than or equal to .001 and P less than or equal to .002, respectively). Likelihood ratio analysis more clearly demonstrated the superiority of In-111 WBC scanning, with positive and negative scans yielding likelihood ratios of 5.0 and 0.16, respectively.

  3. Platelet collagen receptors and coagulation. A characteristic platelet response as possible target for antithrombotic treatment.

    PubMed

    Heemskerk, Johan W M; Kuijpers, Marijke J E; Munnix, Imke C A; Siljander, Pia R M

    2005-04-01

    Collagen is a unique agonist of platelets, because it acts as an immobilized ligand that only causes platelet activation after stable adhesion. This review addresses the present understanding of how platelet interaction with collagen supports the process of thrombin generation and coagulation. Only some of the collagen-adhered platelets, that is, those showing profound changes in shape and shedding microparticles (resembling apoptotic cells), appear to contribute to the procoagulant activity of platelets. The main signaling receptor for collagen, glycoprotein VI, plays a key role in the platelet procoagulant response during thrombus formation; this is a reason why new anti-glycoprotein-VI antibodies are promising antithrombotic tools. PMID:16039967

  4. Detection of microbial contamination in platelets

    NASA Astrophysics Data System (ADS)

    Berg, Tracy L.; Leparc, German; Huffman, Debra E.; Gennaccaro, Angela L.; Garcia-Lopez, Alicia; Klungness, Greta; Stephans, Christie; Garcia-Rubio, Luis H.

    2005-03-01

    In the United States, approximately 100 patients develop fatal sepsis associated with platelet transfusions every year. Current culture methods take 24-48 hours to acquire results, which in turn decrease the shelf life of platelets. Many of the microorganisms that contaminate platelets can replicate easily at room temperature, which is the necessary storage temperature to keep platelets functional. Therefore, there is a need for in-situ quality control assessment of the platelet quality. For this purpose, a real time spectrophotometric technique has been developed. The Spectral Acquisition Processing Detection (SAPD) method, comprised of a UV-vis spectrophotometer and modeling algorithms, is a rapid method that can be performed prior to platelet transfusion to decrease the risk of bacterial infection to patients. The SAPD method has been used to determine changes in cell suspensions, based on size, shape, chemical composition and internal structure. Changes in these cell characteristics can in turn be used to determine microbial contamination, platelet aging and other physiologic changes. Detection limits of this method for platelet suspensions seeded with bacterial contaminants were identified to be less than 100 cfu/ml of sample. Bacterial counts below 1000 cfu/ml are not considered clinically significant. The SAPD method can provide real-time identification of bacterial contamination of platelets affording patients an increased level of safety without causing undue strain on laboratory budgets or personnel while increasing the time frame that platelets can be used by dramatically shortening contaminant detection time.

  5. Characteristics of platelet gels combined with silk

    PubMed Central

    Pallotta, Isabella; Kluge, Jonathan A.; Moreau, Jodie; Calabrese, Rossella

    2014-01-01

    Platelet gel, a fibrin network containing activated platelets, is widely used in regenerative medicine due the capacity of platelet-derived growth factors to accelerate and direct healing processes. However, limitations to this approach include poor mechanical properties, relatively rapid degradation, and the lack of control of release of growth factors at the site of injection. These issues compromise the ability of platelet gels for sustained function in regenerative medicine. In the present study, a combination of platelet gels with silk fibroin gel was studied to address the above limitations. Mixing sonicated silk gels with platelet gels extended the release of growth factors without inhibiting gel forming ability. The released growth factors were biologically active and their delivery was modified further by manipulation of the charge of the silk protein. Moreover, the silk gel augmented both the rheological properties and compressive stiffness of the platelet gel, tuned by the silk concentration and/or silk/platelet gel ratio. Silk-platelet gel injections in nude rats supported enhanced cell infiltration and blood vessel formation representing a step towards new platelet gel formulations with enhanced therapeutic impact. PMID:24480538

  6. Characteristics of platelet gels combined with silk.

    PubMed

    Pallotta, Isabella; Kluge, Jonathan A; Moreau, Jodie; Calabrese, Rossella; Kaplan, David L; Balduini, Alessandra

    2014-04-01

    Platelet gel, a fibrin network containing activated platelets, is widely used in regenerative medicine due the capacity of platelet-derived growth factors to accelerate and direct healing processes. However, limitations to this approach include poor mechanical properties, relatively rapid degradation, and the lack of control of release of growth factors at the site of injection. These issues compromise the ability of platelet gels for sustained function in regenerative medicine. In the present study, a combination of platelet gels with silk fibroin gel was studied to address the above limitations. Mixing sonicated silk gels with platelet gels extended the release of growth factors without inhibiting gel-forming ability. The released growth factors were biologically active and their delivery was modified further by manipulation of the charge of the silk protein. Moreover, the silk gel augmented both the rheological properties and compressive stiffness of the platelet gel, tuned by the silk concentration and/or silk/platelet gel ratio. Silk-platelet gel injections in nude rats supported enhanced cell infiltration and blood vessel formation representing a step towards new platelet gel formulations with enhanced therapeutic impact. PMID:24480538

  7. Thrombospondin-induced adhesion of human platelets.

    PubMed Central

    Tuszynski, G P; Kowalska, M A

    1991-01-01

    Washed human unactivated platelets attached and spread on thrombospondin (TSP)-coated microtiter plates. Platelet adhesion was promoted by divalent cations Mn2+, Mg2+, and Ca2+ as compared to buffer having all divalent cations complexed with EDTA. TSP-dependent adhesion was inhibited by anti-TSP fab fragments, an anti-TSP monoclonal antibody, an RGD-containing peptide, complex-specific anti-glycoprotein (GP)IIb-IIIa monoclonal antibodies (A2A9 or AP-2) and anti-VLA-2 monoclonal antibodies (6F1 and Gi9), but not by rabbit preimmune fab fragments, mouse IgG, an anti-GPIIIa monoclonal antibody, or monoclonal antibodies against either the human vitronectin receptor, glycocalicin, or GPIV. At saturating concentrations, anti-GPIIb-IIIa inhibited adhesion by 40-60%. Glanzman's thrombasthenic platelets, which lack GPIIb-IIIa, adhered to TSP to the same extent as anti-GPIIb-IIIa-treated normal platelets or 40-60% as well as untreated normal platelets. Antibody 6F1 (5-10 micrograms/ml) inhibited platelet adhesion of both normal and thrombasthenic platelets by 84-100%. Both VLA-2 antibodies also inhibited collagen-induced platelet adhesion, but had no effect on fibronectin-induced adhesion of normal platelets. These data indicate that platelets specifically adhere to TSP and that this adhesion is mediated through GPIIb-IIIa and/or VLA-2. Images PMID:2010551

  8. Function of human platelets during extracorporeal circulation.

    PubMed

    Hennessy, V L; Hicks, R E; Niewiarowski, S; Edmunds, L H; Colman, R W

    1977-06-01

    The interaction between human platelets and nonbiologic surfaces was studied during in vitro recirculation of 500 ml of fresh, heparinized human blood in four different perfusion circuits. Circuits differed in surface area (0.1 m2 or 0.9 m2) and in surface composition. No important differences were observed between standard silicone-rubber and filler-free, silicone-rubber surfaces. Platelet counts decreased to 85% of control in 0.1- m2 circuits, but retained normal sensitivity to aggregating agents and released only small amounts of platelet factor 4 (PF4). In contrast, platelet counts in 0.9-m2 circuits decreased to 20% of control within 2 min and platelet sensitivity was depressed out of proportion to the fall in platelet count. Plasma PF4 progressively increased and platelet PF4 content progressively decreased during 6 h of recirculation. The results indicate that human platelets may exist in three conditions during extracorporeal circulation. Some platelets are unaltered, some are less sensitive to aggregating agents, and others have undergone extensive release. The ratio of blood volume to surface area appears to be an important determinant of platelet-surface interaction. PMID:18017

  9. Influence of irradiation on stored platelets

    SciTech Connect

    Moroff, G.; George, V.M.; Siegl, A.M.; Luban, N.L.

    1986-09-01

    Platelet concentrates intended for transfusion to immunosuppressed patients are irradiated to minimize transfusion-induced graft-versus-host disease. Because few reports describe how irradiation influences stored platelets, the authors studied whether 5000 rad of gamma irradiation, the maximum dose currently used clinically, altered platelets in vitro. Platelet concentrates were stored for either 1 day or 5 days in plastic (PL 732) containers before gamma irradiation. One unit of a pair of identical platelet concentrates was irradiated; the second unit served as a control. Irradiation did not alter platelet morphology, mean platelet volume, expression of platelet-factor-3 activity, response to hypotonic stress, extent of discharge of lactate dehydrogenase, release of beta-thromboglobulin, formation of thromboxane B2, nor the ability to undergo synergistic aggregation. The lack of any substantial change was observed whether the platelet concentrates were stored initially for either 1 day or 5 days. These results suggest that stored platelets are not altered deleteriously by irradiation with 5000 rad.

  10. Influence of Oxidative Stress on Stored Platelets

    PubMed Central

    2016-01-01

    Platelet storage and its availability for transfusion are limited to 5-6 days. Oxidative stress (OS) is one of the causes for reduced efficacy and shelf-life of platelets. The studies on platelet storage have focused on improving the storage conditions by altering platelet storage solutions, temperature, and materials. Nevertheless, the role of OS on platelet survival during storage is still unclear. Hence, this study was conducted to investigate the influence of storage on platelets. Platelets were stored for 12 days at 22°C. OS markers such as aggregation, superoxides, reactive oxygen species, glucose, pH, lipid peroxidation, protein oxidation, and antioxidant enzymes were assessed. OS increased during storage as indicated by increments in aggregation, superoxides, pH, conjugate dienes, and superoxide dismutase and decrements in glucose and catalase. Thus, platelets could endure OS till 6 days during storage, due to the antioxidant defense system. An evident increase in OS was observed from day 8 of storage, which can diminish the platelet efficacy. The present study provides an insight into the gradual changes occurring during platelet storage. This lays the foundation towards new possibilities of employing various antioxidants as additives in storage solutions. PMID:26949396

  11. Renal scintigraphy following angiotensin converting enzyme inhibition in the diagnosis of renovascular hypertension (captopril scintigraphy)

    SciTech Connect

    Sfakianakis, G.N. )

    1989-09-01

    This article describes the pathophysiology and primary causes of renovascular hypertension (RVH). No historical or physical finding is specific in the diagnosis of RVH, although onset of hypertension before the age of 30 years may suggest the possible presence of RVH. The physiology of the kidney is described along with the biochemistry of angiotensin converting enzyme inhibitors. The main thrust of the article is nuclear medicine techniques useful in the diagnosis of this disease. Several diagnositic methods are described but captopril scintigraphy is presented as a method that may give more optimal results in the diagnosis of RVH.

  12. Targeting Phosphodiesterases in Anti-platelet Therapy

    PubMed Central

    Rondina, Matthew T.; Weyrich, Andrew S.

    2013-01-01

    There are two primary modes of platelet inhibition: blockade of membrane receptors or neutralization of intracellular pathways. Both means of inhibition have proven benefits in the prevention and resolution of atherothrombotic events. With regard to intracellular inhibition, phosphodiesterases (PDEs) are fundamental for platelet function. Platelets possess several PDEs (PDE2, PDE3 and PDE5) that catalyze the hydrolysis of cyclic adenosine 3′-5′-monophosphate (cAMP) and cyclic guanosine 3′-5′-monophosphate (cGMP), thereby limiting the levels of intracellular nucleotides. PDE inhibitors, such as cilostazol and dipyridamole, dampen platelet function by increasing cAMP and cGMP levels. This review focuses on the roles of PDE inhibitors in modulating platelet function, with particular attention paid to drugs that have anti-platelet clinical indications. PMID:22918733

  13. The Role of Platelets in Venous Thromboembolism.

    PubMed

    Montoro-García, Silvia; Schindewolf, Marc; Stanford, Sophia; Larsen, Ole Halfdan; Thiele, Thomas

    2016-04-01

    Multiple factors contribute to the risk of venous thromboembolism (VTE). Platelets have attracted much interest in arterial cardiovascular disease, whereas their role in VTE has received much less attention. Recent evidence suggests that platelets may play a more important role in VTE than previously anticipated. This review discusses the mechanisms that link platelets with venous thrombotic disease and their potential applications as novel risk factors for VTE. In addition, animal studies and randomized clinical trials that highlight the potential effect of antiplatelet therapy in venous thrombosis are evaluated to assess the role of platelets in VTE. The clinical significance of platelets for VTE risk assessment in specific patient cohorts and their role as a suitable therapeutic target for VTE prevention is acknowledged. The role of platelets in VTE is a promising field for future research. PMID:26926584

  14. Evaluation of platelet cross-matching in the management of patients refractory to platelet transfusions

    PubMed Central

    Salama, Osama S.; Aladl, Doaa A.; El Ghannam, Doaa M.; Elderiny, Wesam E.

    2014-01-01

    Background Cross-match-compatible platelets are used to support thrombocytopenic patients who are refractory to randomly selected platelets. However, few studies have addressed the efficacy of using this strategy for patients requiring intensive platelet transfusion therapy. The aim of this study was to determine the effectiveness of cross-match-compatible platelets in an unselected group of patients refractory to platelets from random donors. Materials and methods A total of 406 cross-match-compatible platelet components were administered to 40 evaluable patients who were refractory to random-donor platelets. A solid-phase red cell adherence method was used for platelet cross-matching. The corrected count increment was used to monitor the effectiveness of each platelet transfusion. Multivariate analysis was performed to detect whether any variables could predict the response to transfusion. Results Statistically significant improvements were found in the mean corrected count increment when comparing cross-match-compatible platelets with randomly selected and incompatible platelets (p<0.001 for each). Compatible platelet transfusions were associated with a good response in 72.9% of cases while incompatible platelets were associated with a poor response in 66.7% of transfusion events (p<0.001). In the presence of clinical factors or alloimmunisation, compatible platelets were associated with good responses in 67.9% and 28.0% respectively vs 100% and 93.3% in their absence (p=0.009, p<0.001). Multivariate analysis revealed that cross-matching and alloimmunisation were the strongest predictors of transfusion response at 1 hour, while ABO compatibility, type of units received, followed by alloimmunisation then clinical factors were predictors at 24 hours. Discussion Platelet cross-matching using the solid-phase red cell adherence technique is an effective and rapid first-line approach for the management of patients refractory to platelet transfusions. PMID:24931840

  15. Extending The Shelf Life Of Blood Platelets

    NASA Technical Reports Server (NTRS)

    Surgenor, Douglas M.

    1988-01-01

    New method of storing human blood platelets extends vitality for transfusions. Packaged as suspension in sterile liquid in plastic blood bags. Each bag placed between pair of plastic grids, and rubberbands placed around sandwich thus formed to hold together. Stored upright in open air or in container through which air pumped at rate of at least 45 L/min. Ensures that platelets receive ample oxygen and expiratory carbon dioxide form platelets removed before pH drops to harmful levels.

  16. Platelet mimicry: The emperor's new clothes?

    PubMed

    Moghimi, Seyed Moein; Hunter, Alan Christy; Peer, Dan

    2016-01-01

    Here we critically examine whether coating of nanoparticles with platelet membranes can truly disguise them against recognition by elements of the innate immune system. We further assess whether the "cloaking technology" can sufficiently equip nanoparticles with platelet-mimicking functionalities to include in vivo targeting of damaged blood vessels and binding to platelet-adhering opportunistic pathogens. We present views for improved, and pharmaceutically viable nanoparticle design strategies. PMID:26409192

  17. [Improvement in cryopreservation of blood platelets].

    PubMed

    Zhiburt, E B; Vil'ianinov, V N; Kaleko, S P; Sidorkevich, S V; Petrenko, G I; Bagautdinov, Sh M; Kuz'min, N S

    2000-01-01

    The first Russian solution Krimolit designed for cryopreservation of platelet concentrates down -196 degrees C was clinically tested. The therapeutical efficacy of the cryopreserved platelets was evaluated on the basis of clinical and laboratory monitoring of transfusions in 20 cancer hematological patients. They were found to have the same therapeutical action as fresh cells. The introduction of cryopreserved platelets into clinical practice allows one to form stores and to transfuse autological cells. Krimolit is recommended for clinical application. PMID:10740789

  18. Digital restoration of indium-111 and iodine-123 SPECT images with optimized Metz filters

    SciTech Connect

    King, M.A.; Schwinger, R.B.; Penney, B.C.; Doherty, P.W.; Bianco, J.A.

    1986-08-01

    A number of radiopharmaceuticals of great current clinical interest for imaging are labeled with radionuclides that emit medium- to high-energy photons either as their primary radiation, or in low abundance in addition to their primary radiation. The imaging characteristics of these radionuclides result in gamma camera image quality that is inferior to that of /sup 99m/Tc images. Thus, in this investigation /sup 111/In and /sup 123/I contaminated with approximately 4% /sup 124/I were chosen to test the hypothesis that a dramatic improvement in planar and SPECT images may be obtainable with digital image restoration. The count-dependent Metz filter is shown to be able to deconvolve the rapid drop at low spatial frequencies in the imaging system modulation transfer function (MTF) resulting from the acceptance of septal penetration and scatter in the camera window. Use of the Metz filter was found to result in improved spatial resolution as measured by both the full width at half maximum and full width at tenth maximum for both planar and SPECT studies. Two-dimensional, prereconstruction filtering with optimized Metz filters was also determined to improve image contrast, while decreasing the noise level for SPECT studies. A dramatic improvement in image quality was observed with the clinical application of this filter to SPECT imaging.

  19. Fused SPECT/CT imaging of Peri-iliopsoas infection using Indium-111-labeled leukocytes.

    PubMed

    Nathan, Jennifer; Crawford, Joseph A; Sodee, D Bruce; Bakale, George

    2006-12-01

    Nuclear imaging with In-111-labeled leukocytes has become an instrumental tool in localizing sites of infection and is superior to Ga-67 in localizing abdominal and pelvic abscesses resulting from absence of a normal bowel excretory pathway. Labeled white blood cells (WBCs) localize at sites of infection through diapedesis, chemotaxis, and enhanced vascular permeability and can thus be used to identify infection. The accuracy of this functional imaging modality can be enhanced by fusing SPECT images of labeled WBC with CT images that provide anatomic detail to facilitate reading as illustrated in the case described. PMID:17117077

  20. Immunoscintigraphy with indium-111 labeled monoclonal antibodies: The importance of a good display method

    SciTech Connect

    Liehn, J.C.; Hannequin, P.; Nasca, S.; Lebrun, D.; Fernandez-Valoni, A.; Valeyre, J. )

    1989-03-01

    A major drawback of In-111-labeled monoclonal antibodies (MoAb) is the presence of intense liver, renal, and bone marrow nonspecific activity. This makes the display of the images hardly optimal and their visual interpretation difficult. In this study, the intrinsic color scale (which consists of selecting the limits of the color scale as the highest and the lowest pixel value of the image) was compared to a new, simple algorithm for the determination of the limits of the color scale. This algorithm was based on the count density in the iliac crest areas. OC-125 or anti-CEA In-111 MoAb F(ab')2 fragments were used in 32 patients with suspected recurrence of ovarian (19 patients) or colorectal cancer (13 patients). Final diagnosis was assessed by surgery (21 patients), biopsy (five patients), or followup (six patients). A 10-minute abdomino-pelvic anterior view was recorded two days after injection. These views are displayed using the two methods and interpreted by two observers. Using their responses in each quadrant of the pelvis, the authors calculated two ROC curves. The comparison of the ROC curves showed better performances for the new method. For example, for the same specificity (73%), the sensitivity of the new method was significantly better (78% versus 68%). This result confirmed the importance of a good methodology for displaying immunoscintigraphic images.

  1. Distribution and imaging of Indium-111 labelled circulating immune complexes (CIC) in humans

    SciTech Connect

    Wirquin, E.; Bruneau, C.; Cinotti, L.; Sobel, A.; Meignan, M.

    1984-01-01

    The clearance of labelled CIC has been widely used to investigate the phagocytic function of the reticuloendothelial system in humans. Many of these studies have been performed with red blood cells (RBC) sensitized with IgG anti Rh and labelled with Cr-51, so that no image of the distribution of these CIC has been presented up to now. The authors obtained such images by using In-111 instead of Cr-51, and compared the values of the clearances provided by each label in 9 normal controls. The In-111 procedure included camera imaging on spleen, liver, heart, lungs and kidneys. Local kinetic-curves were obtained on each organ: 1) The blood clearance values were similar with In-111 (T 1/2 = 23.3 +- 6.4 min) or Cr-51 (T 1/2 = 21.4 +- 4.9); 2) The heart clearance (T 1/2 = 26.6 +- 8.3 min) was not significantly different from the blood T1/.2; 3) There was no uptake of sensitized RBC in lungs and kidneys; 4) Sensitized RBC were mostly cleared by the spleen and T1/2 values were homogenous (20.3 +- 3.8 min); and 5) Sensitized RBC were retained in the liver in 8 out of 9 cases and subsequently released in 5, indicating sequestration without phagocytosis. The variability of the results made it difficult to establish a norm, possibly due to small variations in sensitization, insufficient to influence the spleen T1/2. The authors conclude that sensitized RBC labelled with Cr-51 or In-111 may be used equally well. By camera imaging, the authors identified an hepatic Fc function and could determine the respective role of spleen and liver. IgG sensitized RBC, like their IgM counterparts, were sequestered and released by the liver.

  2. Somatostatin receptor imaging of neuroendocrine tumors with indium-111 pentetreotide (Octreoscan).

    PubMed

    Olsen, J O; Pozderac, R V; Hinkle, G; Hill, T; O'Dorisio, T M; Schirmer, W J; Ellison, E C; O'Dorisio, M S

    1995-07-01

    Somatostatin, a naturally occurring 14-amino acid peptide, can be thought of as an anti-growth hormone and functional down-regulator of sensitive tissue. Most neuroendocrine tumors seem to possess somatostatin receptors in sufficient abundance to allow successful scintigraphic imaging with radiolabeled somatostatin congeners. Several of these, including Indium-III-DTPA Pentetreotide (Octreoscan [Mallinckrodt Medical, St. Louis, MO]), which was approved for clinical use by the Food and Drug Administration in June 1994, have been of considerable value in scintigraphically identifying various neuroendocrine tumors. The Octreoscan compares favorably with other imaging modalities. The success of somatostatin receptor imaging in evaluating patients with suspected neuroendocrine tumors, including identifying otherwise radiographically occult lesions, has resulted in ranking somatostatin receptor imaging as the prime imaging procedure in patients with suspected neuroendocrine tumors at The Ohio State University. PMID:7570044

  3. Autoradiographic method for quantitation of radiolabeled proteins in tissues using indium-111

    SciTech Connect

    Morrell, E.M.; Tompkins, R.G.; Fischman, A.J.; Wilkinson, R.A.; Burke, J.F.; Rubin, R.H.; Strauss, H.W.; Yarmush, M.L. )

    1989-09-01

    A quantitative autoradiographic method was developed to measure 111In-labeled proteins in extravascular tissues with a spatial resolution sufficient to associate these proteins with tissue morphology. A linear relationship between measured grain density and isotope concentration was demonstrated with uniformly-labeled standard sources of epoxy-embedded gelatin containing (111In)albumin; half-distance of spatial resolution was 0.6 micron. The technique was illustrated by measuring 24-hr accumulation of diethylenetriaminepentaacetic acid-coupled 111In-labeled human polyclonal IgG and human serum albumin (HSA) in a thigh infection model in the rat. Gamma camera images localized the infection and showed target-to-background ratios of 2.5 {plus minus} 0.3 for IgG and 1.4 {plus minus} 0.02 for human serum albumin (mean {plus minus} s.d., n = 3). Using quantitative autoradiography, significantly higher average tissue concentrations were found in the infected thighs at 4 to 4.5% of the initial plasma concentrations as compared to 0.2 to 0.3% of initial plasma concentrations in the noninfected thigh (p less than 0.05); these radiolabeled proteins were not inflammatory cell associated and localized primarily within the edematous interstitial spaces of the infection.

  4. Imaging of pharyngeal and laryngeal carcinomas with indium-111-labeled monoclonal anti-CEA antibodies

    SciTech Connect

    Kairemo, K.J.; Hopsu, E.V. )

    1990-10-01

    Localization of primary tumors, metastases, or recurrences in 13 consecutive patients with histological verification of squamous cell or adenocarcinoma was made with radioimmunodetection using monoclonal radiolabeled anti-CEA antibody. All surgical specimens stained immunohistochemically, except one, were positive for CEA. Of the known 19 tumor sites 17 were visualized in antibody scans. There were two positive findings that did not prove to be positive during 12 month follow-up. The scintigram findings did not correlate with CEA serum concentrations that, with one exception, were normal in all patients.

  5. Effect of histocompatibility factors on pulmonary retention of indium-111-labeled granulocytes

    SciTech Connect

    Dutcher, J.P.; Riggs, C. Jr.; Fox, J.J.; Johnston, G.S.; Norris, D.; Wiernik, P.H.; Schiffer, C.A. )

    1990-04-01

    Granulocyte transfusions are associated with a number of side effects including febrile transfusion reactions and occasionally pulmonary infiltrates. There is evidence that the presence of preformed antibodies may be a cause of these complications. In this study, allogeneic 111Indium-labeled granulocytes were used to evaluate the pulmonary retention of radioactivity in alloimmunized and non-alloimmunized patients in an attempt to assess antibody effect on granulocyte migration. After injection of labeled allogeneic granulocytes into neutropenic patients, the ratios of lung to heart activity were calculated for the first 30 min of scanning. There was significantly greater retention of radioactivity from cells in the lungs of patients who were alloimmunized, having both lymphocytotoxic (anti-HLA) and leuko-agglutinating antibodies, compared to the activity in the lungs of non-alloimmunized patients (P less than .001) or of patients receiving autologous granulocytes (P less than .001). This study demonstrates that labeled, mismatched granulocytes may be retained in the lungs for a significantly longer time in patients with preformed antibodies. This implies that transfusion of large numbers of such mismatched granulocytes, i.e., granulocyte transfusions, may also be retained in the lungs of alloimmunized patients, which could lead to pulmonary compromise. Therefore, granulocyte transfusions from random donors should not be given to alloimmunized patients.

  6. Mechanism of ionophoric transport of indium-111 cations through a lipid bilayer membrane

    SciTech Connect

    Choi, H.O.; Hwang, K.J.

    1987-01-01

    The use of mobile ionophores to facilitate the transport of /sup 111/In through a lipid bilayer membrane has broad applications in liposome technology and cell labeling. However, the mechanism of such ionophore-mediated transport of /sup 111/In through a lipid bilayer membrane is not completely clear. The present report describes the correlations of the behaviors of ionophoric loading of /sup 111/In into liposomes with the lipophilicity and the indium-binding affinity of three ionophores, namely, 8-hydroxyquinoline, acetylacetone, and tropolone. Our results suggest that the mechanism of the ionophoric transport of /sup 111/In through a lipid bilayer membrane involves the rapid exchange of /sup 111/In cations among the ionophores in both the aqueous solution and the lipid bilayer. Furthermore, the effectiveness of an ionophore in facilitating the transport of /sup 111/In from the external aqueous compartment to the entrapped nitrilotriacetic acid depends not only on the lipophilicity of the (/sup 111/In)ionophore complex, but also on the lipophilicity of the free ionophore itself and the competition of /sup 111/In between nitrilotriacetic acid inside the inner aqueous compartment of the liposome and the ionophore imbedded in the lipid bilayer membrane of the liposome.

  7. False-positive indium-111 labeled leukocyte scintigram in a patient with a painful hip prosthesis

    SciTech Connect

    Feldman, N.; Makler, P.T. Jr.; Alavi, A.

    1986-01-01

    A Tronzo hip prosthesis is designed to elicit an inflammatory reaction in order to promote prosthesis stability. A three-phased bone scan and Ga-67 imaging in conjunction with physical examination and laboratory findings failed to demonstrate evidence for osteomyelitis in a patient with a painful hip prosthesis, in whom images obtained with In-111-labeled leukocytes were positive. This observation demonstrated that the interpretation of the latter technique in demonstrating inflammation can cause a false impression of an infectious process.

  8. In vitro effects on Indium-111-Oxine labeled leukocytes functions of N-etilmycin

    SciTech Connect

    Iacovo, R.D.; Perna, M.; Esposito, G.; Polese, C.; Frizzi, L.

    1985-05-01

    In order to study in vitro chemotaxis, phagocytosis and bactericydal efficiencies of granulocytes (PMN) and monocytes (Mo) of cancer patients with solid tumours, the authors have undertaken the evaluation of a method of measuring PMN and Mo chemotaxis with modified Boyden chambers, using In-111-oxine. The tests were performed in order to evaluate the interference of N-etilmycin with leukocyte functions, a currently fashionable antibiotic used in the treatment of gram-negative infections. The results both compare well with the visual method and are objective. Cancer patients, disease-free for a minimum of one year, were compared and evidenced normal chemotaxis and normal controls. No difference between the two groups was found (20.46% of those tested). The addition of N-etilmy-cin (6..mu..g/ml) to PMN and Mo further decreased the chemotaxis from 20.46% to 16.07% (t=2.81, P=0.0102). The addition of 30..mu..g/ml further decreased the chemotaxis from the mean control values to 5.925% (t=4.55,P 1%). The use of N-etilmycin in disease-free cancer patients should be avoided in the possible event of tumour enhancement.

  9. Effect of metabolism on retention of indium-111-labeled monoclonal antibody in liver and blood

    SciTech Connect

    Kinuyfa, S.; Jeong, J.M.; Garmestani, K.

    1994-11-01

    The effect of a chelator structure on the metabolic fate of the {sup 111}In-labeled monoclonal antibody (Mab) T101 was investigated in normal Balb/c mice to assess the importance of this chemical parameter in the reduction of the background radioactivity in blood and liver. Mab T101 was conjugated with either 2-(p-isothiocyanatobenzyl)-6-methyl-diethylaminetriaminepentaacetic acid (DTPA) (1B4M), 2-(p-isothiocyanatobenzyl) cyclohexyl-DTPA (CHX-B) or cyclic DTPA dianhydride (cDTPA) and then radiolabeled with {sup 111}In-labeled T101 conjugates and sacrificed in groups of five up to 5 days postinjection for comparative biodistribution studies and analyses of liver, blood and urine samples for radioindium products. The biodistribution of {sup 111}In-1B4M-T101 and {sup 111}In-CHX-B-T101 were similar to each other but significantly different from that of {sup 111}In-cDTPA-T101, particularly in the blood and liver. Size-exclusion high-performance liquid chromatography indicated that the concentration of the intact {sup 111}In-immunoglobulin (Ig)G in liver decreased with similar rates for the three conjugates. Meanwhile, the concentration of a small DTPA-like metabolite in liver increased to a different peak value (4.6% 1D/g for the cDTPA conjugate and 1.6% lD/g for the 1B4M and CHX-B conjugates) approximately at 24 hr and maintained a steady-state concentration up to 5 days. The thiourea linkage between T101 and the {sup 111}In-labeled chelates and a higher complex stability and higher lipophilicity of {sup 111}In-1B4M and {sup 111}In-CHX-B appear to be responsible for lower liver and higher blood radioactivity for the 1B4M and CHX conjugates. 31 refs., 3 figs., 1 tab.

  10. Appearance of hyperostosis frontalis interna on indium-111 leukocyte scans: potential diagnostic pitfall

    SciTech Connect

    Floyd, J.L.; Jackson, D.E. Jr.; Carretta, R.

    1986-04-01

    The appearance of hyperostosis frontalis interna on an (/sup 111/In)leukocyte scan is reported. Recognition of the potential for normal accumulation of 111In-labeled white blood cells within this common process involving the skull is necessary to avoid misdiagnosis.

  11. Platelet C1- inhibitor. A secreted alpha-granule protein.

    PubMed Central

    Schmaier, A H; Smith, P M; Colman, R W

    1985-01-01

    In order to characterize which proteins of the contact phase of coagulation interact with platelets, human platelets were studied immunochemically and functionally to determine if they contain C1- inhibitor. By means of monospecific antibody to C1- inhibitor, a competitive enzyme-linked immunosorbent assay (CELISA) was developed to measure directly platelet C1- inhibitor. With the CELISA, from 33 to 115 ng of C1- inhibitor antigen per 10(8) platelets from 15 normal donors was quantified in lysates of washed human platelets solubilized in nonionic detergent. The mean concentration in 10(8) platelets was 62 +/- 33 ng (SD). Plasma C1- inhibitor either in the platelet suspension medium or on the surface of the platelets could account for only from 6.5 to 16% of the total antigen measured in the solubilized platelets. Upon functional studies, platelets contained 84 +/- 36 ng (SD) of C1- inhibitor activity in 10(8) platelets. As assessed by the CELISA, platelet C1- inhibitor antigen was immunochemically identical to plasma and purified C1- inhibitor. In contrast, the mean concentration of platelet C1- inhibitor antigen in platelets from four patients with classical hereditary angioedema was 8.3 ng/10(8) platelets (range, 5.3 to 11.3 ng/10(8) platelets). 25 and 31% of the total platelet C1- inhibitor was secreted without cell lysis from normal platelets after exposure to collagen (20 micrograms/ml) and thrombin (1 U/ml), respectively, and this secretion was blocked by metabolic inhibitors. Platelet subcellular fractionation showed that platelet C1- inhibitor resided mostly in alpha-granules, similar to the location of platelet fibrinogen. Thus, human platelets contained C1- inhibitor, which became available by platelet secretion. The identification of platelet C1- inhibitor suggests that platelets may modulate the activation of the proteins of early blood coagulation and the classical complement pathways. Images PMID:3965505

  12. Identification of platelet refractoriness in oncohematologic patients

    PubMed Central

    Ferreira, Aline Aparecida; Zulli, Roberto; Soares, Sheila; de Castro, Vagner; Moraes-Souza, Helio

    2011-01-01

    OBJECTIVES: To identify the occurrence and the causes of platelet refractoriness in oncohematologic patients. INTRODUCTION: Platelet refractoriness (unsatisfactory post-transfusion platelet increment) is a severe problem that impairs the treatment of oncohematologic patients and is not routinely investigated in most Brazilian services. METHODS: Forty-four episodes of platelet concentrate transfusion were evaluated in 16 patients according to the following parameters: corrected count increment, clinical conditions and detection of anti-platelet antibodies by the platelet immunofluorescence test (PIFT) and panel reactive antibodies against human leukocyte antigen class I (PRA-HLA). RESULTS: Of the 16 patients evaluated (median age: 53 years), nine (56%) were women, seven of them with a history of pregnancy. An unsatisfactory increment was observed in 43% of the transfusion events, being more frequent in transfusions of random platelet concentrates (54%). Platelet refractoriness was confirmed in three patients (19%), who presented immunologic and non-immunologic causes. Alloantibodies were identified in eight patients (50%) by the PIFT and in three (19%) by the PRA-HLA. Among alloimmunized patients, nine (64%) had a history of transfusion, and three as a result of pregnancy (43%). Of the former, two were refractory (29%). No significant differences were observed, probably as a result of the small sample size. CONCLUSION: The high rate of unsatisfactory platelet increment, refractoriness and alloimmunization observed support the need to set up protocols for the investigation of this complication in all chronically transfused patients, a fundamental requirement for the guarantee of adequate management. PMID:21437433

  13. P2 receptors and platelet function.

    PubMed

    Hechler, Béatrice; Gachet, Christian

    2011-09-01

    Following vessel wall injury, platelets adhere to the exposed subendothelium, become activated and release mediators such as TXA(2) and nucleotides stored at very high concentration in the so-called dense granules. Released nucleotides and other soluble agents act in a positive feedback mechanism to cause further platelet activation and amplify platelet responses induced by agents such as thrombin or collagen. Adenine nucleotides act on platelets through three distinct P2 receptors: two are G protein-coupled ADP receptors, namely the P2Y(1) and P2Y(12) receptor subtypes, while the P2X(1) receptor ligand-gated cation channel is activated by ATP. The P2Y(1) receptor initiates platelet aggregation but is not sufficient for a full platelet aggregation in response to ADP, while the P2Y(12) receptor is responsible for completion of the aggregation to ADP. The latter receptor, the molecular target of the antithrombotic drugs clopidogrel, prasugrel and ticagrelor, is responsible for most of the potentiating effects of ADP when platelets are stimulated by agents such as thrombin, collagen or immune complexes. The P2X(1) receptor is involved in platelet shape change and in activation by collagen under shear conditions. Each of these receptors is coupled to specific signal transduction pathways in response to ADP or ATP and is differentially involved in all the sequential events involved in platelet function and haemostasis. As such, they represent potential targets for antithrombotic drugs. PMID:21792575

  14. Platelet depletion and severity of streptococcal endocarditis

    PubMed Central

    Dall, Lawrence; Miller, Todd; Herndon, Betty; Diez, Ireneo; Dew, Michelle

    1998-01-01

    OBJECTIVE: To evaluate the importance of thrombocytopenia in streptococcal endocarditis using an animal model. DESIGN: A model of human septic endocarditis was established in rats (polyethylene catheters across the aortic valve and administration of Streptococcus sanguis, 5×107 colony forming units [cfu] intravenous). Thrombocytopenia at four levels was produced by antiplatelet serum. Secondary methods of producing thrombocytopenia were also evaluated. At sacrifice (96 h after platelet depletion and 72 h after infection), vegetations were removed, weighed, diluted, plated and counted. Potential mechanisms of the dose-response relationship between vegetation density and platelet count were evaluated. SETTING: Controlled research laboratory experiments. POPULATION STUDIED: Animal models of streptococcal endocarditis. MAIN RESULTS: The bacterial density of the aortic valve vegetations significantly increased as the platelet count decreased (P=0.0007). In severely thrombocytopenic animals (two-dose antiplatelet serum), data suggest increased vegetation embolism. Platelet depletion, which was minimal with chemical methods, was produced most effectively by antithrombocyte serum. Platelet surfaces in endocarditis were found to express elevated CD62p proteins (72.7% endocarditis, 34.7% control). Platelet protein fractions were evaluated in vitro by both streptocidal (P=0.19) and phagocytosis-stimulating assays. Platelet presence in mature aortic valve vegetations averaged only about 2%. CONCLUSIONS: In platelet depletion experiments using a rat model, a dose-response relationship of peripheral circulating platelet depletion to aortic valve vegetation density was found. The mechanism relating thrombocytopenia to endocarditis severity remains unresolved. PMID:22346555

  15. Platelets: covert regulators of lymphatic development.

    PubMed

    Bertozzi, Cara C; Hess, Paul R; Kahn, Mark L

    2010-12-01

    The field of platelet biology has rapidly expanded beyond the classical role of platelets in preventing blood loss and orchestrating clot formation. Despite the lack of transcriptional ability of these anuclear cell fragments, platelet function is now thought to encompass such diverse contexts as tissue repair, immune activation, primary tumor formation, and metastasis. Recent studies from multiple groups have turned the spotlight on an exciting new role for platelets in the formation of lymphatic vessels during embryonic development. Genetic experiments demonstrate that podoplanin, a transmembrane protein expressed on lymphatic endothelial cells, engages the platelet C-type lectin-like receptor 2 (CLEC-2) when exposed to blood, leading to SYK-SLP-76-dependent platelet activation. When components of this pathway are disrupted, aberrant vascular connections form, resulting in blood-lymphatic mixing. Furthermore, platelet-null embryos manifest identical blood-lymphatic mixing. The identification of platelets as the critical cell type mediating blood-lymphatic vascular separation raises new questions in our understanding of lymphatic development and platelet biology. PMID:21071706

  16. Computerised method for recording platelet density distribution.

    PubMed

    Järemo, P

    1995-05-01

    In the present study a computerized apparatus was employed for scanning light transmission variations along test tubes containing density-separated platelets. The device consists of a stepping motor, a stationary halogen lamp and a photopotentiometer connected to a personal computer. Anticoagulated whole blood was layered on a performed continuous Percoll gradient having a density span from 1090 kg/l (bottom) to 1040 kg/l (top). After centrifugation at 3400g for 1.5 hours, high-density cells (i.e. erythrocytes) pass through to the bottom of the test tube and the lighter platelets remain in the gradient. The test tube is moved by the computer between the halogen lamp and the photopotentiometer. Transmission variations along the gradient were recorded and registered in the computer. Density markers beads were used as an internal standard and platelet peak density was determined. After perforating the test tube the gradient was divided into 45 aliquots. In all fractions determination of platelet counts and mean platelet volume was carried out. In addition, in the aliquots having a platelet count > 20 x 10(12)/l the ratio beta-thromboglobulin per platelet was also determined. The platelet distribution in the gradient was illustrated graphically. A good agreement was found when comparing platelet distributions in the gradients and light transmission variations along the test tubes. PMID:7781754

  17. Effect of photodynamic therapy on mouse platelets

    NASA Astrophysics Data System (ADS)

    Zhou, Chuannong; Chi, Shunji; Deng, Jinsheng; Zhang, Hua; Liang, Junlin; Ha, Xian-wen

    1993-03-01

    Normal mice received hematoporphyrin derivative (10 mg/kg iv) immediately, 24 or 48 hrs prior to red light irradiation. The blood was collected and the platelet-rich plasma was irradiated by red light (100 J/cm2). The platelets were fixed immediately, 8 or 16 hrs after irradiation, and processed for EM examination. In comparison with those of control mice, the platelets of all experimental mice showed structural changes: 16 hrs after irradiation all platelets were necrotized; 8 hrs after irradiation almost one fourth of the platelets were necrotized and the remaining were considerably damaged; immediately after irradiation a small number of platelets became necrotic and most other platelets were swollen and deformed, often with many cytoplasmic projections and considerable dilatation of the canalicular membrane system. Our findings provided a clear evidence that platelets are highly sensitive to PDT action and can be directly and rapidly injured by PDT even in the absence of vascular endothelial cells. Our results give firm support to the hypothesis that both endothelial cells and platelets may play an important role in the initiation of early vascular damage and microcirculatory alterations induced by PDT in vivo.

  18. Platelet function tests, independent of platelet count, are associated with bleeding severity in ITP

    PubMed Central

    Grace, Rachael F.; Gerrits, Anja J.; Berny-Lang, Michelle A.; Brown, Travis; Carmichael, Sabrina L.; Neufeld, Ellis J.; Michelson, Alan D.

    2015-01-01

    Immune thrombocytopenia (ITP) patients with similarly low platelet counts differ in their tendency to bleed. To determine if differences in platelet function in ITP patients account for this variation in bleeding tendency, we conducted a single-center, cross-sectional study of pediatric patients with ITP. Bleeding severity (assessed by standardized bleeding score) and platelet function (assessed by whole blood flow cytometry) with and without agonist stimulation was evaluated in 57 ITP patients (median age, 9.9 years). After adjustment for platelet count, higher levels of thrombin receptor activating peptide (TRAP)-stimulated percent P-selectin- and activated glycoprotein (GP)IIb-IIIa–positive platelets were significantly associated with a lower bleeding score, whereas higher levels of immature platelet fraction (IPF), TRAP-stimulated platelet surface CD42b, unstimulated platelet surface P-selectin, and platelet forward light scatter (FSC) were associated with a higher bleeding score. Thus, platelet function tests related to platelet age (IPF, FSC) and activation through the protease activated receptor 1 (PAR1) thrombin receptor (TRAP-stimulated P-selectin, activated GPIIb-IIIa, and CD42b), independent of platelet count, are associated with concurrent bleeding severity in ITP. These tests may be useful markers of future bleeding risk in ITP. PMID:26138687

  19. Useful hepatic parenchymal imaging in hepatobiliary scintigraphy

    SciTech Connect

    Brown, M.L.; Freitas, J.E.; Wahner, H.W.

    1981-05-01

    Hepatobiliary scintigraphy with the 99mTc-labeled iminodiacetic acid derivatives has been shown to be useful in the evaluation of biliary tract diseases, especially for the diagnosis of acute cholecystitis. Little emphasis has been placed on the importance of the hepatic parenchymal image that occurs early in the imaging sequence. To determine what information can be obtained from the hepatic parenchymal image, a comparison was carried out of sulfur colloid and iminodiacetic acid images in 50 patients with focal defects. In 46 of 50 patients, the number and position of lesions on the two studies were similar, while in four patients the images were discordant. In addition to being very similar in lesion detection, the iminodiacetic acid scans also allowed more specificity in the later imaging (biliary phase) in 13 cases. The value of iminodiacetic acid derivatives in the evaluation of some biliary tract disorders has been established; considerable value can also be obtained by close inspection of the hepatic parenchymal image as well.

  20. Busulfan Triggers Intrinsic Mitochondrial-Dependent Platelet Apoptosis Independent of Platelet Activation.

    PubMed

    Qiao, Jianlin; Wu, Yulu; Liu, Yun; Li, Xiaoqian; Wu, Xiaoqing; Liu, Na; Zhu, Feng; Qi, Kunming; Cheng, Hai; Li, Depeng; Li, Hongchun; Li, Zhenyu; Zeng, Lingyu; Ma, Ping; Xu, Kailin

    2016-09-01

    As a nonspecific alkylating antineoplastic agent, busulfan has been widely used in the treatment of patients with chronic myeloid leukemia. In vitro and in vivo studies demonstrated busulfan-induced cell apoptosis. Whether busulfan triggers platelet apoptosis remains unclear. This study aimed to evaluate the role of busulfan in platelet apoptosis. Isolated human platelets were incubated with busulfan followed by analysis of platelet apoptosis by flow cytometry or western blot, including mitochondrial depolarization, expression of Bcl-2, and Bax and caspase 3 activation. Meanwhile, platelet activation, expression of glycoprotein Ibα (GPIbα), glycoprotein VI (GPVI), and IIb3 and platelet aggregation in response to collagen and adenosine diphosphate (ADP) were measured. Additionally, busulfan was injected into mice with or without administration of caspase inhibitor QVD-Oph to investigate its effect on platelet lifespan. Our results showed that busulfan-treated platelets displayed increased mitochondrial membrane depolarization, decreased expression of Bcl-2, increased expression of Bax and caspase 3 activation in dose-dependent manner, which were inhibited by QVD-Oph. Platelet activation was not observed in busulfan-treated platelets as showed by no increased P-selectin expression and PAC-1 binding. However, busulfan reduced collagen- or ADP-induced platelet aggregation without affecting expression of GPIbα, GPVI, and IIb3. Furthermore, busulfan reduced circulating platelet lifespan which was ameliorated by QVD-Oph in mice. In conclusion, busulfan triggers mitochondrial-dependent platelet apoptosis and reduces platelet lifespan in mice. These data suggest targeting caspase activation might be beneficial in the prophylaxis of platelet apoptosis-associated thrombocytopenia after administration of busulfan. PMID:27292166

  1. Metalloproteolytic receptor shedding…platelets "acting their age".

    PubMed

    Andrews, Robert K; Gardiner, Elizabeth E

    2016-09-01

    Whilst significant effort has been focused on development of tools and approaches to clinically modulate activation processes that consume platelets, the platelet receptors that initiate activation processes remain untargeted. The modulation of receptor levels is also linked to underlying platelet aging processes which influence normal platelet lifespan and also the functionality and survival of stored platelets that are used in transfusion. In this review, we will focus on platelet adhesion receptors initiating thrombus formation, and discuss how regulation of levels of these receptors impact platelet function and platelet survival. PMID:27459696

  2. Expansion of the neonatal platelet mass is achieved via an extension of platelet lifespan

    PubMed Central

    Liu, Zhi-Jian; Hoffmeister, Karin M.; Hu, Zhongbo; Mager, Donald E.; Ait-Oudhia, Sihem; Debrincat, Marlyse A.; Pleines, Irina; Josefsson, Emma C.; Kile, Benjamin T.; Italiano, Joseph; Ramsey, Haley; Grozovsky, Renata; Veng-Pedersen, Peter; Chavda, Chaitanya

    2014-01-01

    The fetal/neonatal hematopoietic system must generate enough blood cells to meet the demands of rapid growth. This unique challenge might underlie the high incidence of thrombocytopenia among preterm neonates. In this study, neonatal platelet production and turnover were investigated in newborn mice. Based on a combination of blood volume expansion and increasing platelet counts, the platelet mass increased sevenfold during the first 2 weeks of murine life, a time during which thrombopoiesis shifted from liver to bone marrow. Studies applying in vivo biotinylation and mathematical modeling showed that newborn and adult mice had similar platelet production rates, but neonatal platelets survived 1 day longer in circulation. This prolonged lifespan fully accounted for the rise in platelet counts observed during the second week of murine postnatal life. A study of pro-apoptotic and anti-apoptotic Bcl-2 family proteins showed that neonatal platelets had higher levels of the anti-apoptotic protein Bcl-2 and were more resistant to apoptosis induced by the Bcl-2/Bcl-xL inhibitor ABT-737 than adult platelets. However, genetic ablation or pharmacologic inhibition of Bcl-2 alone did not shorten neonatal platelet survival or reduce platelet counts in newborn mice, indicating the existence of redundant or alternative mechanisms mediating the prolonged lifespan of neonatal platelets. PMID:24599546

  3. In vivo effects of eltrombopag on platelet function in immune thrombocytopenia: no evidence of platelet activation

    PubMed Central

    Psaila, Bethan; Bussel, James B.; Linden, Matthew D.; Babula, Bracken; Li, Youfu; Barnard, Marc R.; Tate, Chinara; Mathur, Kanika; Frelinger, Andrew L.

    2012-01-01

    The effects of eltrombopag, a thrombopoietin-receptor agonist, on platelet function in immune thrombocytopenia (ITP) are not fully characterized. This study used whole blood flow cytometry to examine platelet function in 20 patients receiving eltrombopag treatment at days 0, 7, and 28. Platelet surface expression of activated GPIIb/IIIa, P-selectin, and GPIb was measured with and without low and high adenosine diphosphate (ADP) and thrombin receptor activating peptide (TRAP) concentrations. Before eltrombopag treatment with no ex vivo agonist, platelet activation was higher in ITP patients than controls. Platelet GPIb and activated GPIIb/IIIa expression without added agonist was unchanged following eltrombopag treatment, whereas a slight increase in P-selectin was observed. Expression of P-selectin and activated GPIIb/IIIa in response to high-dose ADP was lower during eltrombopag treatment than at baseline. Eltrombopag led to a slight increase in platelet reactivity to TRAP only in responders to eltrombopag but not to levels above those in controls; whole blood experiments demonstrated that this increase was probably because of higher platelet counts rather than higher platelet reactivity. In conclusion, although thrombocytopenic ITP patients have higher baseline platelet activation than controls, eltrombopag did not cause platelet activation or hyper-reactivity, irrespective of whether the platelet count increased. PMID:22294727

  4. IgG platelet antibodies in EDTA-dependent pseudothrombocytopenia bind to platelet membrane glycoprotein IIb.

    PubMed

    Fiorin, F; Steffan, A; Pradella, P; Bizzaro, N; Potenza, R; De Angelis, V

    1998-08-01

    EDTA-dependent pseudothrombocytopenia (PTCP) consists of an inappropriate low platelet count caused by autoantibodies present in the serum samples reacting with platelets only in EDTA-anticoagulated blood. By using immunoprecipitation and Western blot techniques, we studied the immunochemical specificity of platelet agglutinating autoantibodies in the serum samples of 10 patients with PTCP. Furthermore, to evaluate a possible role of PTCP-associated IgG autoantibodies in increased platelet turnover, we assayed the plasma glycocalicin (GC) level and calculated the GC index for every patient. Our results provide direct evidence that an epitope located on platelet membrane glycoprotein IIb is recognized by PTCP-associated IgG antibodies; moreover GC levels in patients with EDTA-dependent PTCP were similar to control levels, thus excluding an increased platelet turnover. We conclude that antiplatelet antibodies directed against platelet cryptantigens are unlikely to have a major role in the increased removal of cells from circulation. PMID:9704616

  5. Reticulated platelets: analytical aspects and clinical utility.

    PubMed

    Hoffmann, Johannes J M L

    2014-08-01

    Reticulated platelets are immature platelets circulating in blood; they reflect the activity of megakaryopoiesis in the bone marrow. Therefore, they can be used as a non-invasive test in patients with thrombocytopenia in various clinical conditions. The preferred method of analysis is by flow cytometry. However, there is an evident lack of analytical standardization, making it difficult to compare results obtained in different laboratories. Currently, two types of hematology analyzers are on the market offering fully automated measurement of reticulated or immature platelets: the high end analyzers manufactured by Sysmex (XE- and XN-series) and Abbott (CELL-DYN Sapphire). Although the methods are essentially different and cannot be used interchangeably, both have been proven to have clinical utility. Reticulated or immature platelet assays are useful for the differential diagnosis of thrombocytopenia and for monitoring bone marrow recovery after chemotherapy or stem cell transplantation. These assays may aid clinicians in platelet transfusion decisions when recovery from thrombocytopenia is imminent. In addition, preliminary findings indicate that there is a rationale for reticulated or immature platelets for risk stratification in acute coronary syndromes and for monitoring the effect of treatment with antiplatelet drugs in patients with coronary artery diseases. The aim of this paper is to present the present technology available for measuring reticulated platelets as well as an overview of the current status of clinical application. This overview also indicates that more research is needed before reticulated or immature platelet assays can be applied in other clinical conditions than thrombocytopenia and after transplantation. PMID:24807169

  6. Platelets and fibrin strands during clot retraction.

    PubMed

    Morgenstern, E; Korell, U; Richter, J

    1984-03-15

    The ultrastructure of platelet fibrin contacts (PFC) and the course of the strands was investigated in serial sections of retracted clots with the help of specimen tilting. We found after retraction in a test tube as well as under isometric conditions in the resonance thrombograph, after HARTERT, an uniform type of PFC. The side to side contact between platelet surface and fibrin strands displayed a 15 nm wide space which was bridged of 10 - 30 nm by filamentary structure. In each case the direction of the fibrin strands changed on contact with the platelet surface (bend). These bends recurred if the adhering strands ran over a longer distance on the platelet surface. The bends can be explained by non-directional movement of the platelets or of their pseudopodia. Microfilaments (actomyosin) which run straight in pseudopodia and often also twisted in the platelet body support this assumption. The described mechanism - contact of the thrombin activated platelets with fibrin strands and simultaneous nondirectional movement of the platelets which bind further sections of the adhering strands to their surface - would provide a more satisfactory explanation for the retraction of the clot to 1/10 of its original volume. PMID:6539004

  7. Platelet generation in vivo and in vitro.

    PubMed

    Wang, Biao; Zheng, Jiansheng

    2016-01-01

    Platelet (PLT) transfusion, which is the primary cell therapy for thrombocytopenia, has been a source of concern in recent years due to its limitations of donor-dependent supply and soaring costs. In vitro platelet generation on an industrial scale is a possible solution requiring exploration. The technology of platelet generation ex vivo has been widely studied across the world, though the mechanisms of physiological thrombopoiesis and platelet biology function in vivo still remain elusive today. Various culture systems have been studied, most of which proved quite inefficient in generating functional platelets ex vivo, so there is still a long way to reach our ultimate goal of generating a fully functional platelet in vitro on an industrial scale. This review integrates the latest research into physiological platelet biogenesis and ex vivo-platelet/megakaryocyte (MK) generation protocols with a focus on the ability to generate PLT/MK in large quantities, summarizes current culture systems based on induced human pluripotent stem cells and adipose-derived stem cells, and discusses significant challenges that must be overcome for these approaches to be perfected. PMID:27390629

  8. Titanium surface hydrophilicity enhances platelet activation.

    PubMed

    Alfarsi, Mohammed A; Hamlet, Stephen M; Ivanovski, Saso

    2014-01-01

    Titanium implant surface modification is a key strategy used to enhance osseointegration. Platelets are the first cells that interact with the implant surface whereupon they release a wide array of proteins that influence the subsequent healing process. This study therefore investigated the effect of titanium surface modification on the attachment and activation of human platelets. The surface characteristics of three titanium surfaces: smooth (SMO), micro-rough (SLA) and hydrophilic micro-rough (SLActive) and the subsequent attachment and activation of platelets following exposure to these surfaces were determined. The SLActive surface showed the presence of significant nanoscale topographical features. While attached platelets appeared to be morphologically similar, significantly fewer platelets attached to the SLActive surface compared to both the SMO and SLA surfaces. The SLActive surface however induced the release of the higher levels of chemokines β-thromboglobulin and platelet factor 4 from platelets. This study shows that titanium surface topography and chemistry have a significant effect on platelet activation and chemokine release. PMID:25311339

  9. Fractal and Euclidean descriptors of platelet shape.

    PubMed

    Kraus, Max-Joseph; Neeb, Heiko; Strasser, Erwin F

    2014-01-01

    Platelet shape change is a dynamic membrane surface process that exhibits remarkable morphological heterogeneity. Once the outline of an irregular shape is identified and segmented from a digital image, several mathematical descriptors can be applied to numerical characterize the irregularity of the shapes surface. 13072 platelet outlines (PLO) were segmented automatically from 1928 microscopic images using a newly developed algorithm for the software product Matlab R2012b. The fractal dimension (FD), circularity, eccentricity, area and perimeter of each PLO were determined. 972 PLO were randomly assigned for computer-assisted manual measurement of platelet diameter as well as number, width and length of filopodia per platelet. FD can be used as a surrogate parameter for determining the roughness of the PLO and circularity can be used as a surrogate to estimate the number and length of filopodia. The relationship between FD and perimeter of the PLO reveals the existence of distinct groups of platelets with significant structural differences which may be caused by platelet activation. This new method allows for the standardized continuous numerical classification of platelet shape and its dynamic change, which is useful for the analysis of altered platelet activity (e.g. inflammatory diseases, contact activation, drug testing). PMID:24224894

  10. Sodium-hydrogen exchange and platelet function.

    PubMed

    Rosskopf, D

    1999-07-01

    On stimulation of platelets with agonists, for example, thrombin, a rapid rise in intracellular pH is observed. This alkalinization is mediated by an increase in transport activity of the Na(+)/H(+) exchanger isoform NHE1. In addition to this Na(+)/H(+) exchange mechanism, platelets express bicarbonate/chloride exchangers, which also contribute to pH(i) homeostasis. The main functions of NHE1 in platelets include pH(i) control, volume regulation, and participation in cell signaling. The isoform NHE1 is highly sensitive toward inhibition by EIPA, Hoe694, and Hoe642. The regulation of NHE1 activity is complex and is not completely understood. It includes the MAP kinase cascade, the Ca/calmodulin system, several heterotrimeric G proteins (Galpha12, Galpha13, Galphaq, and Galphai), small G proteins (ras, cdc42, rhoA), and downstream kinases (e.g., p160ROCK). Volume challenges stimulate tyrosine phosphorylation of cytoplasmic proteins, which ultimately activate NHE1. Thrombin, thromboxane, platelet-activating factor, angiotensin II, endothelin, phorbol ester, and Ca(2+) ionophors stimulate NHE1 activity in platelets. Blockade of platelet NHE1 can inhibit platelet activation. With the development of highly specific NHE1 inhibitors, detailed investigation of the relationships between NHE1 activity and platelet activation now becomes feasible. PMID:10481210

  11. Relation of platelet density to platelet age: survival of low- and high-density 111indium-labeled platelets in baboons

    SciTech Connect

    Savage, B.; McFadden, P.R.; Hanson, S.R.; Harker, L.A.

    1986-08-01

    The relationship between platelet density and platelet age has been studied using continuous linear Percoll density gradients and 111In-labeling of autologous platelets in baboons. To investigate changes in platelet density during senescence in the circulation, baboons were infused with 111In-labeled autologous platelets, and blood was collected at one hour postinfusion and twice daily thereafter for six days. Platelets were isolated from these samples in high yield (greater than 95%) and separated in continuous linear Percoll density gradients following density equilibrium centrifugation. Although at one hour postinfusion the density distribution of radiolabeled platelets coincided closely with the distribution of the total platelet population, a detectable symmetrical shift toward higher densities was observed after five days. The relative specific radioactivity (RSR) of high-density platelets (1.064 to 1.067 g/mL) decreased at a slower rate than that of the total platelet population (platelets of all densities), whereas the RSR of low-density platelets (1.053 to 1.056 g/mL) showed a more immediate and rapid decrease. These results give rise to one of two interpretations: (1) low-density platelets have a shorter survival time than more dense platelets and are therefore cleared from the circulation at a faster rate, or (2) platelets of all densities increase in density upon aging in the circulation. To determine the explanation for changing RSR of different density fractions we studied the in vivo disappearance characteristics of low- and high-density 111In-labeled platelets. There were no significant differences between the mean survival times of low-density platelets (5.0 +/- 0.49 days, +/- 1 SD, n = 6), high-density platelets (4.9 +/- 0.56 days, n = 6), or control platelets representing platelets of all densities (4.9 +/- 0.38 days, n = 6).

  12. Relationship between potential platelet activation and LCS

    NASA Astrophysics Data System (ADS)

    Shadden, Shawn

    2010-11-01

    In the study of blood flow, emphasis is often directed at understanding shear stress at the vessel wall due to its potentially disruptive influence on the endothelium. However, it is also known that shear stress has a potent effect on platelet activation. Platelet activation is a precursor for blood clotting, which in turn is the cause of most forms of death. Since most platelets are contained in the flow domain, it is important to consider stresses acting on the platelet as they are convected. Locations of high stress can correspond to boundaries between different dynamic regions and locations of hyperbolic points in the Eulerian sense. In the computation of LCS, strain in typically considered in the Lagrangian sense. In this talk we discuss the relationship between locations of potential platelet activation due to increased stress and locations of LCS marking increase Lagrangian deformation.

  13. Platelets and coagulation in infection

    PubMed Central

    Davis, Rachelle P; Miller-Dorey, Sarah; Jenne, Craig N

    2016-01-01

    Disseminated intravascular coagulation (DIC) is a frequent complication in sepsis that is associated with worse outcomes and higher mortality in patients. In addition to the uncontrolled generation of thrombi throughout the patient's vasculature, DIC often consumes large quantities of clotting factors leaving the patient susceptible to hemorrhaging. Owing to these complications, patients often receive anticoagulants to treat the uncontrolled clotting, often with mixed outcomes. This lack of success with the current array of anticoagulants can be partly explained by the fact that during sepsis clotting is often initiated by the immune system. Systemic inflammation has the capacity to activate and amplify coagulation and, as such, potential therapies for the treatment of sepsis-associated DIC need to address the interaction between inflammation and coagulation. Recent studies have suggested that platelets and neutrophil extracellular traps (NETs) are the key mediators of infection-induced coagulation. This review explores current anticoagulant therapies and discusses the development of future therapies to target platelet and NET-mediated coagulation. PMID:27525062

  14. Platelet interaction within giant intracranial aneurysms

    SciTech Connect

    Sutherland, G.R.; King, M.E.; Peerless, S.J.; Vezina, W.C.; Brown, G.W.; Chamberlain, M.J.

    1982-01-01

    Turbulence within intracranial aneurysms may result in tearing of the aneurysmal wall, exposing the subendothelial matrix to circulating platelets. In this study, platelet interaction in giant intracranial aneurysms was evaluated by a dual-isotope technique employing In-labeled platelets and Tc-labeled red blood cells. The use of two isotopes allows the subtraction of the blood pool and the calculation of the ratio indium deposited:indium blood pool (In(D)/In(BP)). A ratio greater than zero indicates platelet deposition within aneurysm. Thirteen patients were evaluated in this way, with platelet deposition demonstrated in six. In these six patients, the ratio In(D)/In(BP) was found to be significantly elevated, with a mean value of 0.96 +/- 0.65. Three of these six patients has symptoms of recurrent transient neurological deficits; one of these three suffered a complete stroke following documentation of platelet deposition. In this case, the aneurysm was obtained at surgery and was found to contain intraluminal platelet aggregation when viewed by scanning electron microscopy. In the remaining seven patients, the ratio IN(D)/In(BP) was found not to be significantly elevated (mean -0.03 and/- 0.06), indicating the absence of active platelet deposition. Two of these patients had prior symptoms of cerebral ischemia; one of these was found to have an ulcer in the ipsilateral internal carotid artery which was probably responsible for thromboembolic events to the hemisphere. The authors conclude that platelet aggregation occurs more frequently than previously recognized in giant intracranial aneurysms, and their data substantiate the hypothesis that platelet metabolic products or thrombi originating from a large aneurysm may embolize to distal cerebral vessels.

  15. [Imaging of thromboembolism by scintigraphy with the 99m-technetium-labelled synthetic peptide P280].

    PubMed

    Lastoria, S; Vergara, E; Varrella, P; Muto, P; Acampa, W; Caracò, C; Salvatore, M

    1995-12-01

    P280, a synthetic peptide composed of 26 aminoacids, has high affinity (Kd = 100 nM) and specificity for the glycoprotein IIb/IIIa (GPIIb/IIIa) receptor expressed on activated platelets. In this study we investigated the potential usefulness of imaging deep vein thrombosis (DVT) and pulmonary embolism (PE) in humans with 99mTc-P280. In 15 patients (9 men and 6 women; mean age +/- s.d.: 49.2 +/- 14.1) with known DVT and/or PE, serial images were acquired within 24 hours of the injection of approximately 200 micrograms of P280 radiolabelled with 10-23 mCi of 99mTc. P280 was labelled with the ligand exchange method using 99mTc-glucoheptonate. Rapid blood clearance (< or = 5% ID was still circulating in 1 hour) enabled identification of thrombi as early as 60 minutes after the injection, with significant thrombi-to-background ratios (range: 2-4) in 11/15 patients (73%), in 7/9 with DVT, in 2/3 with PE and in 2/3 patients with both DVT and PE. Radiotracer uptake was clearly detectable also in late scans, which confirms that 99mTc-P280 specifically binds to the thrombi through a receptor-mediated mechanism. PE localizations were detectable 3-4 hours after peptide injection, and in 2 cases SPECT enabled the detection of thrombi missed on planar views. Conversely, the test was negative in 4 patients who had the onset of clinical symptoms and the diagnosis of DVT and/or PE more than 40 days before scintigraphy. The lack of 99mTc-P280 uptake in the latter patients suggested that the peptide does not bind to thrombi when thrombogenesis is not active. These preliminary results clearly indicate scintigraphy with 99mTc-P280 to be a suitable, noninvasive and highly specific tool to image fresh clots causing DVT and/or PE. Thus, this technique might overcome the limitations of the imaging procedures currently in use. PMID:8685469

  16. Mean platelet size related to glycoprotein-specific autoantibodies and platelet-associated IgG.

    PubMed

    Javela, K; Kekomäki, R

    2007-12-01

    Recent evidence suggests that platelet-associated glycoprotein-specific (GP) antibodies represent true positive autoantibodies and can therefore be taken as the gold standard. Earlier tests, which aimed at detecting platelet-associated IgG (PA-IgG), might have been hampered, e.g. by the variation of platelet size in thrombocytopenic patients. In this study, 206 samples with increased PA-IgG from consecutive thrombocytopenic patients were tested further for GP-specific antibodies with a monoclonal antibody immobilized platelet antigen test (MAIPA) using a combination of a GP IIbIIIa-specific and a GP IbIX-specific antibody for immobilization or, in a separate assay, GP V-specific antibody. Mean platelet size was recorded as forward scatter (FSC) of platelets in flow cytometric analysis of PA-IgG. GP-specific antibodies were detected in 49 (24%) of the 206 patient samples. Their presence correlated well with increased PA-IgG (R = 0.769). The mean platelet size and mean fluorescence intensity (MFI) of PA-IgG were both significantly increased in patients compared with healthy controls (n = 112; P < 0.0001). Notably, PA-IgG was associated with platelet size within the platelet population of both healthy controls and patients (R = 0.999). Further, the probability of GP IIbIIIa and/or IbIX and GP V-specific PA-IgG tended to increase with the mean platelet size of the patients (P = 0.045). In conclusion, large platelets bound more IgG than platelets of normal size, which may explain at least in part the reported low specificity of total PA-IgG measurement. As the PA-IgG displays low specificity compared with the gold standard, its use as such may be abandoned and replaced by tests for platelet-associated GP-specific autoantibodies. PMID:17988298

  17. Mean platelet size related to glycoprotein-specific autoantibodies and platelet-associated IgG

    PubMed Central

    JAVELA, K; KEKOMÄKI, R

    2007-01-01

    Recent evidence suggests that platelet-associated glycoprotein-specific (GP) antibodies represent true positive autoantibodies and can therefore be taken as the gold standard. Earlier tests, which aimed at detecting platelet-associated IgG (PA-IgG), might have been hampered, e.g. by the variation of platelet size in thrombocytopenic patients. In this study, 206 samples with increased PA-IgG from consecutive thrombocytopenic patients were tested further for GP-specific antibodies with a monoclonal antibody immobilized platelet antigen test (MAIPA) using a combination of a GP IIbIIIa-specific and a GP IbIX-specific antibody for immobilization or, in a separate assay, GP V-specific antibody. Mean platelet size was recorded as forward scatter (FSC) of platelets in flow cytometric analysis of PA-IgG. GP-specific antibodies were detected in 49 (24%) of the 206 patient samples. Their presence correlated well with increased PA-IgG (R = 0.769). The mean platelet size and mean fluorescence intensity (MFI) of PA-IgG were both significantly increased in patients compared with healthy controls (n = 112; P < 0.0001). Notably, PA-IgG was associated with platelet size within the platelet population of both healthy controls and patients (R = 0.999). Further, the probability of GP IIbIIIa and/or IbIX and GP V-specific PA-IgG tended to increase with the mean platelet size of the patients (P = 0.045). In conclusion, large platelets bound more IgG than platelets of normal size, which may explain at least in part the reported low specificity of total PA-IgG measurement. As the PA-IgG displays low specificity compared with the gold standard, its use as such may be abandoned and replaced by tests for platelet-associated GP-specific autoantibodies. PMID:17988298

  18. Northern elephant seal platelets: analysis of shape change and response to platelet agonists.

    PubMed

    Field, C L; Walker, N J; Tablin, F

    2001-02-15

    Blood platelets have a vital role in the maintenance of normal mammalian hemostasis. Rapid pressure changes and temperatures lower than 20 degrees C cause activation of human and terrestrial mammal platelets. Elephant seals are routinely subjected to pressures as high as 150 atm, yet do not suffer from the thrombotic effects of platelet activation associated with rapid decompression. We examined the ultrastructure of Northern elephant seal (Mirounga angustirostris) platelets and their functional and morphological response to various platelet agonists. Unstimulated elephant seal platelets are discoid cells, with a microtubule coil, randomly dispersed alpha and dense granules, and glycogen granules. There are well-defined areas of membranous invaginations that indicate the presence of an open canalicular system (OCS). Aggregometry was used to determine the response of elephant seal platelets to various platelet agonists. Dose-dependent curves were generated for thrombin, collagen, and adenosine diphosphate (ADP). Platelet response to thrombin was dose-dependent and was maximal at 2.5 U/ml. Platelets collected in sodium citrate had blunted responses to both ADP and collagen. ADP stimulation caused only reversible, primary activation (shape change) at > or = 5 microM, while platelets did not aggregate in response to any concentration of collagen. Platelets collected in sodium heparin did respond fully to both to ADP and collagen. There was small, reversible shape change in response to ristocetin, but no response to epinephrine. Decreased sensitivity of elephant seal platelets to agonists may be a protective mechanism developed in response to rapid pressure changes and cold temperatures associated with adaptation to an extreme environment. PMID:11248288

  19. Breaking the Mold: Transcription Factors in the Anucleate Platelet and Platelet-Derived Microparticles

    PubMed Central

    Lannan, Katie L.; Sahler, Julie; Kim, Nina; Spinelli, Sherry L.; Maggirwar, Sanjay B.; Garraud, Olivier; Cognasse, Fabrice; Blumberg, Neil; Phipps, Richard P.

    2015-01-01

    Platelets are small anucleate blood cells derived from megakaryocytes. In addition to their pivotal roles in hemostasis, platelets are the smallest, yet most abundant, immune cells and regulate inflammation, immunity, and disease progression. Although platelets lack DNA, and thus no functional transcriptional activities, they are nonetheless rich sources of RNAs, possess an intact spliceosome, and are thus capable of synthesizing proteins. Previously, it was thought that platelet RNAs and translational machinery were remnants from the megakaryocyte. We now know that the initial description of platelets as “cellular fragments” is an antiquated notion, as mounting evidence suggests otherwise. Therefore, it is reasonable to hypothesize that platelet transcription factors are not vestigial remnants from megakaryocytes, but have important, if only partly understood functions. Proteins play multiple cellular roles to minimize energy expenditure for maximum cellular function; thus, the same can be expected for transcription factors. In fact, numerous transcription factors have non-genomic roles, both in platelets and in nucleated cells. Our lab and others have discovered the presence and non-genomic roles of transcription factors in platelets, such as the nuclear factor kappa β (NFκB) family of proteins and peroxisome proliferator-activated receptor gamma (PPARγ). In addition to numerous roles in regulating platelet activation, functional transcription factors can be transferred to vascular and immune cells through platelet microparticles. This method of transcellular delivery of key immune molecules may be a vital mechanism by which platelet transcription factors regulate inflammation and immunity. At the very least, platelets are an ideal model cell to dissect out the non-genomic roles of transcription factors in nucleated cells. There is abundant evidence to suggest that transcription factors in platelets play key roles in regulating inflammatory and hemostatic

  20. Fish-eye sign in scintigraphy of benign thyroid nodule

    SciTech Connect

    Vaqueiro, M.; Gharib, H.; Wahner, H.W.

    1985-11-01

    An unusual scintigraphic appearance of a benign adenomatous nodule in the thyroid is described which showed a central core of functional tissue surrounded by a rim of nonfunctioning tissue and degenerative changes. The descriptive term fish-eye sign is proposed. The characterization of tissue by scintigraphy prior to fine needle aspiration may be helpful in its interpretation.

  1. Accuracy of Hepatobiliary Scintigraphy after Liver Transplantation and Liver Resection

    PubMed Central

    Ackermann, Hanns; Bechstein, Wolf O.; Grünwald, Frank

    2016-01-01

    Background and Aims. Biliary complications are the most frequent complications after common liver surgeries. In this study, accuracy of hepatobiliary scintigraphy (HBS) and impact of hyperbilirubinemia were evaluated. Methods. Between November 2007 and February 2016, 131 patients underwent hepatobiliary scintigraphy after having liver surgery. 39 patients with 42 scans after LTX (n = 13) or hepatic resection (n = 26) were evaluated in the study; 27 were male, with mean age 60 years. The subjects underwent hepatobiliary scintigraphy with Tc-99m labeled Mebrofenin. The results were compared to ERCP as gold standard performed within one month after HBS. We calculated sensitivity, specificity, PPV, and NPV. We compared LTX patients to patients with other liver surgeries. Furthermore the influence of hyperbilirubinemia on HBS scans was evaluated. Results. HBS always provided the correct diagnosis in cases of bile leak in the liver-resected group (14/14). Overall diagnostic accuracy was 76% (19/25) in this group and 54% (7/13) in the LTX group. False negative (FN) diagnoses occurred more often among LTX patients (p = 0.011). Hyperbilirubinemia (>5 mg/dL) significantly influenced the excretion function of the liver, prolonging HBS's time-activity-curve (p = 0.001). Conclusions. Hepatobiliary scintigraphy is a reliable tool to detect biliary complications, but reduced accuracy must be considered after LTX. PMID:27563464

  2. Noninvasive external cardiac pacing for thallium-201 scintigraphy

    SciTech Connect

    Feldman, M.D.; Warren, S.E.; Gervino, E.V.; Aroesty, J.M.; Royal, H.D.; Parker, J.A.; Silverman, K.J.; Kolodny, G.M.; Zoll, P.M.; McKay, R.G.

    1988-01-01

    Improvements in noninvasive external cardiac pacing have led to a technique with reliable electrical capture and tolerable patient discomfort. To assess the use of this modality of pacing in combination with thallium scintigraphy as a noninvasive pacing stress test, we applied simultaneous noninvasive cardiac pacing, hemodynamic monitoring, and thallium-201 scintigraphy in 14 patients undergoing cardiac catheterization for chest pain syndromes. Two patients had normal coronary arteries, while the remaining 12 had significant coronary artery disease. Thallium scintigraphic responses to pacing were compared to routine exercise thallium stress testing in nine of these 14 patients. All patients were noninvasively paced to more than 85% of the age-predicted maximum heart rate. Twelve patients demonstrated reversible thallium defects, which corresponded in 11 cases to significant lesions seen on coronary angiography. Of nine patients who underwent both pacing and exercise thallium stress tests, comparable maximal rate-pressure products were achieved. Moreover, thallium imaging at peak pacing and during delayed views did not differ significantly from exercise thallium scintigraphy. A limiting factor associated with the technique was local patient discomfort, which occurred to some degree in all patients. We conclude that noninvasive external cardiac pacing together with thallium scintigraphy is capable of detecting significant coronary artery disease and may be comparable to routine exercise thallium stress testing. This new modality of stress testing could be useful in patients unable to undergo the exercise required for standard exercise tolerance testing, particularly if improvements in the technology can be found to reduce further the local discomfort.

  3. Quality assessment of platelet concentrates prepared by platelet rich plasma-platelet concentrate, buffy coat poor-platelet concentrate (BC-PC) and apheresis-PC methods

    PubMed Central

    Singh, Ravindra P.; Marwaha, Neelam; Malhotra, Pankaj; Dash, Sumitra

    2009-01-01

    Background: Platelet rich plasma-platelet concentrate (PRP-PC), buffy coat poor-platelet concentrate (BC-PC), and apheresis-PC were prepared and their quality parameters were assessed. Study Design: In this study, the following platelet products were prepared: from random donor platelets (i) platelet rich plasma - platelet concentrate (PRP-PC), and (ii) buffy coat poor-platelet concentrate (BC-PC) and (iii) single donor platelets (apheresis-PC) by different methods. Their quality was assessed using the following parameters: swirling, volume of the platelet concentrate, platelet count, WBC count and pH. Results: A total of 146 platelet concentrates (64 of PRP-PC, 62 of BC-PC and 20 of apheresis-PC) were enrolled in this study. The mean volume of PRP-PC, BC-PC and apheresis-PC was 62.30±22.68 ml, 68.81±22.95 ml and 214.05±9.91 ml and ranged from 22-135 ml, 32-133 ml and 200-251 ml respectively. The mean platelet count of PRP-PC, BC-PC and apheresis-PC was 7.6±2.97 × 1010/unit, 7.3±2.98 × 1010/unit and 4.13±1.32 × 1011/unit and ranged from 3.2 –16.2 × 1010/unit, 0.6-16.4 × 1010/unit and 1.22-8.9 × 1011/unit respectively. The mean WBC count in PRP-PC (n = 10), BC-PC (n = 10) and apheresis-PC (n = 6) units was 4.05±0.48 × 107/unit, 2.08±0.39 × 107/unit and 4.8±0.8 × 106/unit and ranged from 3.4 -4.77 × 107/unit, 1.6-2.7 × 107/unit and 3.2 – 5.2 × 106/unit respectively. A total of 26 units were analyzed for pH changes. Out of these units, 10 each were PRP-PC and BC-PC and 6 units were apheresis-PC. Their mean pH was 6.7±0.26 (mean±SD) and ranged from 6.5 – 7.0 and no difference was observed among all three types of platelet concentrate. Conclusion: PRP-PC and BC-PC units were comparable in terms of swirling, platelet count per unit and pH. As expected, we found WBC contamination to be less in BC-PC than PRP-PC units. Variation in volume was more in BC-PC than PRP-PC units and this suggests that further standardization is required for

  4. Brief Report: Platelet-Poor Plasma Serotonin in Autism

    ERIC Educational Resources Information Center

    Anderson, George M.; Hertzig, Margaret E.; McBride, P. A.

    2012-01-01

    Possible explanations for the well-replicated platelet hyperserotonemia of autism include an alteration in the platelet's handling of serotonin (5-hydroxyserotonin, 5-HT) or an increased exposure of the platelet to 5-HT. Measurement of platelet-poor plasma (PPP) levels of 5-HT appears to provide the best available index of in vivo exposure of the…

  5. The York Platelet Syndrome: a third case.

    PubMed

    White, James G; Gunay-Aygun, Meral

    2011-01-01

    Our present study has described a third patient with the York Platelet Syndrome (YPS). The condition consists of a mitochondrial myopathy associated with unique platelet pathology. Their mitochondrial myopathy has not been completely delineated and will be the subject of further study. Platelet pathology in the new patient is essentially identical to that described in the first two patients. Thin sections of her thrombocytes reveal a normal complement of α and δ granules (dense bodies) in some, a decreased number in others and complete absence in a few. The unique pathological feature is the presence of giant organelles, including an intensely electron dense, huge body, the opaque organelle (OO) and a multilayered large body, the target organelle. In addition platelets from the new patient contain large masses and coils of smooth endoplasmic reticulum present infrequently in platelets of the first two patients. The giant opaque and target organelles appear to develop in rough and smooth endoplasmic reticulum of the parent megakaryocyte and mature in the dense tubular system of circulating platelets. The relationship of the unique platelet pathology and mitochondrial myopathy has not been defined. PMID:21117861

  6. Nanoparticle biointerfacing by platelet membrane cloaking.

    PubMed

    Hu, Che-Ming J; Fang, Ronnie H; Wang, Kuei-Chun; Luk, Brian T; Thamphiwatana, Soracha; Dehaini, Diana; Nguyen, Phu; Angsantikul, Pavimol; Wen, Cindy H; Kroll, Ashley V; Carpenter, Cody; Ramesh, Manikantan; Qu, Vivian; Patel, Sherrina H; Zhu, Jie; Shi, William; Hofman, Florence M; Chen, Thomas C; Gao, Weiwei; Zhang, Kang; Chien, Shu; Zhang, Liangfang

    2015-10-01

    Development of functional nanoparticles can be encumbered by unanticipated material properties and biological events, which can affect nanoparticle effectiveness in complex, physiologically relevant systems. Despite the advances in bottom-up nanoengineering and surface chemistry, reductionist functionalization approaches remain inadequate in replicating the complex interfaces present in nature and cannot avoid exposure of foreign materials. Here we report on the preparation of polymeric nanoparticles enclosed in the plasma membrane of human platelets, which are a unique population of cellular fragments that adhere to a variety of disease-relevant substrates. The resulting nanoparticles possess a right-side-out unilamellar membrane coating functionalized with immunomodulatory and adhesion antigens associated with platelets. Compared to uncoated particles, the platelet membrane-cloaked nanoparticles have reduced cellular uptake by macrophage-like cells and lack particle-induced complement activation in autologous human plasma. The cloaked nanoparticles also display platelet-mimicking properties such as selective adhesion to damaged human and rodent vasculatures as well as enhanced binding to platelet-adhering pathogens. In an experimental rat model of coronary restenosis and a mouse model of systemic bacterial infection, docetaxel and vancomycin, respectively, show enhanced therapeutic efficacy when delivered by the platelet-mimetic nanoparticles. The multifaceted biointerfacing enabled by the platelet membrane cloaking method provides a new approach in developing functional nanoparticles for disease-targeted delivery. PMID:26374997

  7. Transport of platelets in flowing blood.

    PubMed

    Eckstein, E C; Bilsker, D L; Waters, C M; Kippenhan, J S; Tilles, A W

    1987-01-01

    Distribution and transport of platelets in flowing blood were studied experimentally using suspensions of washed red cells and fluorescent latex beads as platelet analogues. Distributions of the platelet analogues were obtained from stroboscopic epifluorescence photomicrographs of flow in 50-micron channels and from images of the cut cross sections of cryogenically frozen thin-walled 200-micron tubes. Concentration profiles of platelet analogues had a substantial near-wall excess for situations with a substantial hematocrit (greater than 10%) and a substantial wall shear rate (greater than 400 s-1). The viscosity of the suspending fluid was found to affect the size of the near-wall excess and its shear-dependent onset. Additionally, the shear-rate dependence of the near-wall excess did not occur with suspensions of hardened red cells. The excess extended a substantial distance from the wall in the 200-micron tubes and a portion of the profile could be fitted to an exponential curve. The random walk model that is used to describe enhanced platelet diffusion is envisioned as a walk (lateral platelet motion) caused by shear-induced collisions with red cells. A more comprehensive random walk model that includes biased collisions produces an effective lateral motion of convective nature in addition to a diffusional motion; it is used to explain the observed nonuniform distributions of platelet analogues. PMID:3439741

  8. Nanoparticle biointerfacing via platelet membrane cloaking

    PubMed Central

    Hu, Che-Ming J.; Fang, Ronnie H.; Wang, Kuei-Chun; Luk, Brian T.; Thamphiwatana, Soracha; Dehaini, Diana; Nguyen, Phu; Angsantikul, Pavimol; Wen, Cindy H.; Kroll, Ashley V.; Carpenter, Cody; Ramesh, Manikantan; Qu, Vivian; Patel, Sherrina; Zhu, Jie; Shi, William; Hofman, Florence M.; Chen, Thomas C.; Gao, Weiwei; Zhang, Kang; Chien, Shu; Zhang, Liangfang

    2015-01-01

    Development of functional nanoparticles can be encumbered by unanticipated material properties and biological events, which can negatively impact nanoparticle effectiveness in complex, physiologically relevant systems1–3. Despite the advances in bottom-up nanoengineering and surface chemistry, reductionist functionalization approaches remain inadequate in replicating the complex interfaces present in nature and cannot avoid exposure of foreign materials. Here we report on the preparation of polymeric nanoparticles enclosed in the plasma membrane of human platelets, which are a unique population of cellular fragments that adhere to a variety of disease-relevant substrates4–7. The resulting nanoparticles possess a right-side-out unilamellar membrane coating functionalized with immunomodulatory and adhesion antigens associated with platelets. As compared to uncoated particles, the platelet membrane-cloaked nanoparticles have reduced cellular uptake by macrophage-like cells and are absent of particle-induced complement activation in autologous human plasma. The cloaked nanoparticles also display platelet-mimicking properties such as selective adhesion to damaged human and rodent vasculatures as well as enhanced binding to platelet-adhering pathogens. In an experimental rat model of coronary restenosis and a mouse model of systemic bacterial infection, docetaxel and vancomycin, respectively, show enhanced therapeutic efficacy when delivered by the platelet-mimetic nanoparticles. The multifaceted biointerfacing enabled by the platelet membrane cloaking method provides a new approach in developing functional nanoparticles for disease-targeted delivery. PMID:26374997

  9. Platelet antibody: review of detection methods

    SciTech Connect

    Schwartz, K.A.

    1988-10-01

    The driving force behind development of in vitro methods for platelet antibodies is identification of plasma factors causing platelet destruction. Early methods relied on measurement of platelet activation. Current methods are more specific and use a purified antibody against immunoglobulin or complement, which is usually labeled with /sup 125/I or tagged with an enzyme or fluorescein. Comparisons of quantitation of platelet-associated IgG show wide variability between different methods. The disparate results can be related both to differences in binding of secondary antibodies to immunoglobulin in solution compared to immunoglobulins attached to platelets and to the improper assumption that the binding ratio between the secondary detecting and primary antiplatelet antibody is one. Most assays can 1) identify neonatal isoimmune thrombocytopenia and posttransfusion purpura, 2) help to differentiate between immune and nonimmune thrombocytopenias, 3) help to sort out the offending drug when drug-induced thrombocytopenia is suspected, and 4) identify platelet alloantibodies and potential platelet donors via a cross match assay for refractory patients. However, the advantages of quantitative assays over qualitative methods with respect to predictions of patients clinical course and response to different treatments remain to be investigated. 61 references.

  10. The role of platelets in sepsis.

    PubMed

    de Stoppelaar, Sacha F; van 't Veer, Cornelis; van der Poll, Tom

    2014-10-01

    Platelets are small circulating anucleate cells that are of crucial importance in haemostasis. Over the last decade, it has become increasingly clear that platelets play an important role in inflammation and can influence both innate and adaptive immunity. Sepsis is a potentially lethal condition caused by detrimental host response to an invading pathogen. Dysbalanced immune response and activation of the coagulation system during sepsis are fundamental events leading to sepsis complications and organ failure. Platelets, being major effector cells in both haemostasis and inflammation, are involved in sepsis pathogenesis and contribute to sepsis complications. Platelets catalyse the development of hyperinflammation, disseminated intravascular coagulation and microthrombosis, and subsequently contribute to multiple organ failure. Inappropriate accumulation and activity of platelets are key events in the development of sepsis-related complications such as acute lung injury and acute kidney injury. Platelet activation readouts could serve as biomarkers for early sepsis recognition; inhibition of platelets in septic patients seems like an important target for immune-modulating therapy and appears promising based on animal models and retrospective human studies. PMID:24966015

  11. Alterations of platelet aggregation kinetics with ultraviolet laser emission: the "stunned platelet" phenomenon.

    PubMed

    Topaz, O; Minisi, A J; Bernardo, N L; McPherson, R A; Martin, E; Carr, S L; Carr, M E

    2001-10-01

    Platelets, a major constituent of thrombus, play a crucial role in the pathogenesis of acute ischemic coronary syndromes. The effect of ultraviolet laser emission on platelets within thrombi is unknown. The effects of increasing levels of laser energy on platelets in whole blood were investigated. Blood samples were obtained by aseptic venipuncture and anticoagulated with 3.8% sodium citrate. Samples were exposed to increased levels (0, 30, 45, 60 mJ/mm2; 25 Hz) of ultraviolet excimer laser fluence (308 nm wave-length) and then tested for ADP and collagen induced platelet aggregation, platelet concentration, and for platelet contractile force (PCF) development. Scanning electron microscopy was used to detect laser induced morphologic changes of platelets and by flow cytometric analysis to detect changes in expression of platelet surface antigens p-selectin (CD 62) and glycoprotein IIb/IIIa (CD 43). Exposure to excimer laser energy produced dose dependent suppression of platelet aggregation and force development ("stunned platelets"). ADP aggregation decreased from 8.0+/-1.1 Ohms (mean+/-SEM) to 3.7+/-0.8 Ohms (p<0.001) to 2.7+/-0.6 Ohms (p <0.001) and to 1.8+/-0.5 Ohms (p <0.001) as the laser energy increased from 0 to 30 to 45 to 60 mJ/mm2, respectively. Collagen induced aggregation decreased from 21.4+/-1.4 Ohms to 15.7+/-1.2 Ohms (p <0.001) to 11.7+/-1.1 Ohms (p <0.001) and to 9.9+/-1.0 Ohms (p <0.001), in response to the same incremental range of laser energy. Platelet contractile forces declined from 34,500+/-3700 to 27.800+/-2700 dynes as laser energy increased from 0 to 60 mJ/mm2 (p <0.03). Platelet concentration did not change with increasing laser energy. The expression of platelet surface antigen p-selectin (CD 62) remained stable through increasing levels of laser energy exposures while the percentage of CD 43 positive platelets significantly increased with exposure to laser energy, yet the level of expression did not exceed 0.5% of cells. Thus

  12. Analysis of aggregation of platelets in thrombosis

    NASA Astrophysics Data System (ADS)

    Ahuja, Suresh

    Platelets are key players in thrombus formation by first rolling over collagen bound von Willebrand factor followed by formation of a stable interaction with collagen. The first adhered platelets bind additional platelets until the whole injury is sealed off by a platelet aggregate. The coagulation system stabilizes the formed platelet plug by creating a tight fibrin network, and then wound contraction takes place because of morphological changes in platelets. Coagulation takes place by platelet activation and aggregation mainly through fibrinogen polymerization into fibrin fibers. The process includes multiple factors, such as thrombin, plasmin, and local shear-rate which regulate and control the process. Coagulation can be divided into two pathways: the intrinsic pathway and the extrinsic pathway. The intrinsic pathway is initiated by the exposure of a negatively charged. It is able to activate factor XII, using a complex reaction that includes prekallikrein and high-molecular-weight kininogen as cofactors.. Thrombin is the final enzyme that is needed to convert fibrinogen into fibrin. The extrinsic pathway starts with the exposure of tissue factor to the circulating blood, which is the major initiator of coagulation. There are several feedback loops that reinforce the coagulation cascade, resulting in large amounts of thrombin. It is dependent on the presence of pro-coagulant surfaces of cells expressing negatively charged phospholipids--which include phosphatidylserine (PS)--on their outer membrane. PS-bearing surfaces are able to increase the efficiency of the reactions by concentrating and co-localizing coagulation factors.. Aggregation of platelets are analyzed and compared to adhesion of platelet to erythrocyte and to endothelial cells. This abstract is replacing MAR16-2015-020003.

  13. Decreased mean platelet volume in panic disorder

    PubMed Central

    Göğçegöz Gül, Işıl; Eryılmaz, Gül; Özten, Eylem; Hızlı Sayar, Gökben

    2014-01-01

    Aim The relationship between psychological stress and platelet activation has been widely studied. It is well known that platelets may reflect certain biochemical changes that occur in the brain when different mental conditions occur. Platelet 5-hydroxytryptamine (5-HT) is also extensively studied in psychiatry. The mean platelet volume (MPV), the accurate measure of platelet size, has been considered a marker and determinant of platelet function. The aim of the present study was to search for any probable difference in the MPV of subjects with panic disorder (PD). Methods A total of 37 drug-free subjects, aged 18 to 65 years, diagnosed with PD, with or without agoraphobia, according to the Diagnostic and Statistical Manual of Mental Disorders, Fourth edition (DSM-IV) criteria and 45 healthy control subjects were included in the study. Platelet count and MPV were measured and recorded for each subject. Results There were no statistically significant differences between groups in terms of female/male ratio, age, or body mass index between the PD group and control group (P=0.91, P=0.82, and P=0.93, respectively). The MPV was found to be significantly lower in the PD group compared with the control group (8.8±0.9 fL vs 9.2±0.8 fL; P=0.02). All the participants had MPV values in the standard range of 6.9–10.8 fL. Conclusion We concluded that abnormalities of the 5-HT1A receptor function in the central nervous system of subjects with a diagnosis of PD are also mirrored in as an alteration in platelet activity. Measurements of platelet activity may be used as a tool for neuropsychiatric and psychopharmacological research and for studying how certain mental diseases and medications affect the central nervous system. PMID:25214790

  14. Platelet activity in the pathophysiology of inflammatory bowel diseases.

    PubMed

    Chen, Chunqiu; Li, Yongyu; Yu, Zhen; Liu, Zhanju; Shi, Yanhong; Lewandowska, Urszula; Sobczak, Marta; Fichna, Jakub; Kreis, Martin

    2015-01-01

    Platelets play a crucial role in immune responses. Impaired platelet activation may cause persistent mucosal inflammation through P-selectin, CD40-CD40L and other systems influencing granulocytes, macrophages or endothelial cells. Pharmacological regulation of platelet activation may reduce thromboembolism and limit the interaction of platelets with endothelial and inflammatory cells, in turn weakening the inflammatory responses. In this review we focus on pathophysiological activities of platelets in inflammatory bowel diseases and discuss the studies on currently available anti-platelet therapies in the treatment of gastrointestinal inflammation. Finally, we provide a prospective view to new anti-platelet agents currently under development. PMID:25585124

  15. Imipramine binding in subpopulations of normal human blood platelets

    SciTech Connect

    Arora, R.C.; Meltzer, H.Y.

    1984-02-01

    Imipramine binding was studied in platelet membranes isolated with different proportions of heavy (young) and light (old) platelets. The B/sub max/, a measure of the number of binding sites, was greater in the heavier platelets than in the light platelets. However, the dissociation constant K/sub d/ (a reflection of the affinity of imipramine binding) was greater in the lighter platelets compared to the heavy platelets. These results indicate that differences in K/sub d/ and B/sub max/ in particular membrane preparation, could be due to the differences in the relative proportion of heavy and light platelets.

  16. Platelet-cytokine Complex Suppresses Tumour Growth by Exploiting Intratumoural Thrombin-dependent Platelet Aggregation

    PubMed Central

    Li, Yu-Tung; Nishikawa, Tomoyuki; Kaneda, Yasufumi

    2016-01-01

    Tumours constitute unique microenvironments where various blood cells and factors are exposed as a result of leaky vasculature. In the present study, we report that thrombin enrichment in B16F10 melanoma led to platelet aggregation, and this property was exploited to administer an anticancer cytokine, interferon-gamma induced protein 10 (IP10), through the formation of a platelet-IP10 complex. When intravenously infused, the complex reached platelet microaggregates in the tumour. The responses induced by the complex were solely immune-mediated, and tumour cytotoxicity was not observed. The complex suppressed the growth of mouse melanoma in vivo, while both platelets and the complex suppressed the accumulation of FoxP3+ regulatory T cells in the tumour. These results demonstrated that thrombin-dependent platelet aggregation in B16F10 tumours defines platelets as a vector to deliver anticancer cytokines and provide specific treatment benefits. PMID:27117228

  17. Secrets of platelet exocytosis – what do we really know about platelet secretion mechanisms?

    PubMed Central

    Golebiewska, Ewelina M; Poole, Alastair W

    2014-01-01

    Upon activation by extracellular matrix components or soluble agonists, platelets release in excess of 300 active molecules from intracellular granules. Those factors can both activate further platelets and mediate a range of responses in other cells. The complex microenvironment of a growing thrombus, as well as platelets' roles in both physiological and pathological processes, require platelet secretion to be highly spatially and temporally regulated to ensure appropriate responses to a range of stimuli. However, how this regulation is achieved remains incompletely understood. In this review we outline the importance of regulated secretion in thrombosis as well as in ‘novel’ scenarios beyond haemostasis and give a detailed summary of what is known about the molecular mechanisms of platelet exocytosis. We also discuss a number of theories of how different cargoes could be released in a tightly orchestrated manner, allowing complex interactions between platelets and their environment. PMID:24588354

  18. Platelets: the few, the young, and the active.

    PubMed

    D'Souza, Carol; Briggs, Carol; Machin, Samuel J

    2015-03-01

    Many modern automated cell counters in high-volume clinical hematology laboratories use new, improved technologies for routine platelet analysis. The latest progress includes the use of state-of-the art information technology, specific fluorescent dyes, and monoclonal antibodies to obtain more reliable platelet counts. This information allows the accurate and precise enumeration of platelets even in thrombocytopenic patients and the reporting of novel platelet parameters. In the near future, digital image analysis may permit even better platelet analysis. PMID:25676376

  19. Evaluation of platelet thromboxane radioimmunoassay method to measure platelet life-span: Comparison with /sup 111/indium-platelet method

    SciTech Connect

    Vallabhajosula, S.; Machac, J.; Badimon, L.; Lipszyc, H.; Goldsmith, S.J.; Fuster, V.

    1985-05-01

    The platelet activation during radiolabeling in vitro with Cr-51 and In-111 may affect the platelet life-span (PLS) in vivo. A new RIA method to measure PLS is being evaluated. Aspirin inhibits platelet thromboxane (TxA/sub 2/) by acetylating cyclooxygenase. The time required for the TxA/sub 2/ levels to return towards control values depends on the rate of new platelets entering circulation and is a measure of PLS. A single dose of aspirin (150mg) was given to 5 normal human subjects. Blood samples were collected for 2 days before aspirin and daily for 10 days. TxA/sub 2/ production in response to endogenous thrombin was studied by allowing 1 ml blood sample to clot at 37/sup 0/C for 90 min. Serum TxB/sub 2/ (stable breakdown product of Tx-A/sub 2/) levels determined by RIA technique. The plot of TxB/sub 2/ levels (% control) against time showed a gradual increase. The PLS calculated by linear regression analysis assuming a 2-day lag period before cyclooxygenase recovery is 9.7 +- 2.37. In the same 5 subjects, platelets from a 50ml blood sample were labeled with /sup 111/In-tropolone in 2 ml autologous plasma. Starting at 1 hr after injection of labeled platelets, 10 blood samples were obtained over a 8 day period. The PLS calculated based on a linear regression analysis is 10.2 +. 1.4. The PLS measured from the rate of platelet disappearance from circulation and the rate of platelet regeneration into circulation are quite comparable in normal subjects. TxA/sub 2/ regeneration RIA may provide a method to measure PLS without administering radioactivity to patient.

  20. Regulation of platelet biology by platelet endothelial cell adhesion molecule-1.

    PubMed

    Jones, Chris I; Moraes, Leonardo A; Gibbins, Jonathan M

    2012-01-01

    Platelet endothelial cell adhesion molecule-1 (PECAM-1), an immunoreceptor tyrosine-based inhibitory motif containing receptor, plays diverse and apparently contradictory roles in regulating the response of platelets to stimuli; inhibiting platelet response to immunoreceptor tyrosine-based activation motif and G protein-coupled receptor signalling following stimulation with collagen, adenosine diphosphate, and thrombin, as well as enhancing integrin outside-in signalling. These dual, and opposing, roles suggest an important and complex role for PECAM-1 in orchestrating platelet response to vascular damage. Indeed, during thrombus formation, the influence of PECAM-1 on the multiple signalling pathways combines leading to a relatively large inhibitory effect on thrombus formation. PMID:22035359

  1. Anticoagulation inhibits tumor cell-mediated release of platelet angiogenic proteins and diminishes platelet angiogenic response.

    PubMed

    Battinelli, Elisabeth M; Markens, Beth A; Kulenthirarajan, Rajesh A; Machlus, Kellie R; Flaumenhaft, Robert; Italiano, Joseph E

    2014-01-01

    Platelets are a reservoir for angiogenic proteins that are secreted in a differentially regulated process. Because of the propensity for clotting, patients with malignancy are often anticoagulated with heparin products, which paradoxically offer a survival benefit by an unknown mechanism. We hypothesized that antithrombotic agents alter the release of angiogenesis regulatory proteins from platelets. Our data revealed that platelets exposed to heparins released significantly decreased vascular endothelial growth factor (VEGF) in response to adenosine 5'-diphosphate or tumor cells (MCF-7 cells) and exhibited a decreased angiogenic potential. The releasate from these platelets contained decreased proangiogenic proteins. The novel anticoagulant fondaparinux (Xa inhibitor) demonstrated a similar impact on the platelet angiogenic potential. Because these anticoagulants decrease thrombin generation, we hypothesized that they disrupt signaling through the platelet protease-activated receptor 1 (PAR1) receptor. Addition of PAR1 antagonists to platelets decreased VEGF release and angiogenic potential. Exposure to a PAR1 agonist in the presence of anticoagulants rescued the angiogenic potential. In vivo studies demonstrated that platelets from anticoagulated patients had decreased VEGF release and angiogenic potential. Our data suggest that the mechanism by which antithrombotic agents increase survival and decrease metastasis in cancer patients is through attenuation of platelet angiogenic potential. PMID:24065244

  2. Understanding platelet generation from megakaryocytes: implications for in vitro–derived platelets

    PubMed Central

    Sim, Xiuli; Poncz, Mortimer; Gadue, Paul

    2016-01-01

    Platelets are anucleate cytoplasmic discs derived from megakaryocytes that circulate in the blood and have major roles in hemostasis, thrombosis, inflammation, and vascular biology. Platelet transfusions are required to prevent the potentially life-threatening complications of severe thrombocytopenia seen in a variety of medical settings including cancer therapy, trauma, and sepsis. Platelets used in the clinic are currently donor-derived which is associated with concerns over sufficient availability, quality, and complications due to immunologic and/or infectious issues. To overcome our dependence on donor-derived platelets for transfusion, efforts have been made to generate in vitro–based platelets. Work in this area has advanced our understanding of the complex processes that megakaryocytes must undergo to generate platelets both in vivo and in vitro. This knowledge has also defined the challenges that must be overcome to bring in vitro–based platelet manufacturing to a clinical reality. This review will focus on our understanding of committed megakaryocytes and platelet release in vivo and in vitro, and how this knowledge can guide the development of in vitro–derived platelets for clinical application. PMID:26787738

  3. Platelet utilization: a Canadian Blood Services research and development symposium.

    PubMed

    Webert, Kathryn E; Alam, Asim Q; Chargé, Sophie B; Sheffield, William P

    2014-04-01

    Considerable progress has been made in recent years in understanding platelet biology and in strengthening the clinical evidence base around platelet transfusion thresholds and appropriate platelet dosing. Platelet alloimmunization rates have also declined. Nevertheless, controversies and uncertainties remain that are relevant to how these products can best be used for the benefit of platelet transfusion recipients. Platelets are unique among the blood products directly derived from whole blood or apheresis donations in requiring storage, with shaking, at ambient temperature. Storage is accordingly constrained between the need to limit the growth of any microbes in the product and the need to minimize losses in platelet function associated with storage. Proteomic and genomic approaches are being applied to the platelet storage lesion. Platelet inventory management is made challenging by these constraints. Although bacterial screening has enhanced the safety of platelet transfusions, pathogen reduction technology may offer further benefits. Continuing clinical investigations are warranted to understand the value of transfusing platelets prophylactically or only in response to bleeding in different patient groups and how best to manage the most grievously injured trauma patients. Patients refractory to platelet transfusions also require expert clinical management. The engineering of platelet substitute products is an active area of research, but considerable hurdles remain before any clinical uses may be contemplated. Roles for platelets in biological areas distinct from hemostasis are also emerging. Platelet utilization is variably affected by all of the above factors, by demographic changes, by new medications, and by new patient care approaches. PMID:24629305

  4. 21 CFR 640.20 - Platelets.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... one unit of blood and resuspended in an appropriate volume of original plasma, as prescribed in § 640.24(d). (b) Source. The source material for Platelets is plasma which may be obtained by whole...

  5. 21 CFR 640.20 - Platelets.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... one unit of blood and resuspended in an appropriate volume of original plasma, as prescribed in § 640.24(d). (b) Source. The source material for Platelets is plasma which may be obtained by whole...

  6. 21 CFR 640.20 - Platelets.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... one unit of blood and resuspended in an appropriate volume of original plasma, as prescribed in § 640.24(d). (b) Source. The source material for Platelets is plasma which may be obtained by whole...

  7. 21 CFR 640.20 - Platelets.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... one unit of blood and resuspended in an appropriate volume of original plasma, as prescribed in § 640.24(d). (b) Source. The source material for Platelets is plasma which may be obtained by whole...

  8. Mapuche Herbal Medicine Inhibits Blood Platelet Aggregation

    PubMed Central

    Falkenberg, Susan Skanderup; Tarnow, Inge; Guzman, Alfonso; Mølgaard, Per; Simonsen, Henrik Toft

    2012-01-01

    12 plant species traditionally used by the Mapuche people in Chile to treat wounds and inflammations have been evaluated for their direct blood platelet inhibition. Seven of the 12 tested plant species showed platelet inhibitory effect in sheep blood, and four of these were also able to inhibit the ADP- (5.0 μM) and collagen- (2.0 μg/mL) induced aggregations in human blood. These four species in respective extracts (in brackets) were Blechnum chilense (MeOH), Luma apiculata (H2O), Amomyrtus luma (DCM : MeOH 1 : 1) and Cestrum parqui (DCM : MeOH 1 : 1). The platelet aggregating inhibitory effects of A. luma (DCM : MeOH 1 : 1), and L. apiculata (H2O) were substantial and confirmed by inhibition of platelet surface activation markers. PMID:22028732

  9. DISSOLUTION AND CRYSTALLIZATION OF CALCIUM SULFITE PLATELETS

    EPA Science Inventory

    The paper discusses the dissolution and crystallization of calcium sulfite platelets. The rates of calcium sulfite dissolution and crystallization are important in slurry scrubbing processes for flue gas desulfurization. The rates affect the scrubber solution composition, SO2 abs...

  10. Acid soluble, pepsin resistant platelet aggregating material

    SciTech Connect

    Schneider, M.D.

    1982-08-31

    Disclosed is an acid soluble, pepsin resistant, platelet aggregating material isolated from equine arterial tissue by extraction with dilute aqueous acid. The method of isolation and use to control bleeding are described. 4 figs.

  11. Platelet transfusion therapy: from 1973 to 2005.

    PubMed

    Brand, Anneke; Novotny, Vera; Tomson, Bert

    2006-06-01

    Platelet transfusions are indispensable for supportive care of patients with hematological diseases. We describe the developments in platelet products for transfusion since the 1970s, when, in particular, support for patients with allo-antibodies against human leukocyte antigens was a laborious exercise with a high failure rate. Currently, due to many stepwise innovations, platelet transfusions are of low immunogenicity and sufficiently available, they have a shelf life up to 7 days, and even matched platelets can often be routinely delivered, provided that there is good communication between all partners in the chain. Future improvements can be expected from uniform type and screen approaches for immunized patients and cross-matching by computer. For efficient use of health care resources, blood banks and stem cell donor banks could share their typed donor files. PMID:16728262

  12. 21 CFR 640.20 - Platelets.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... one unit of blood and resuspended in an appropriate volume of original plasma, as prescribed in § 640.24(d). (b) Source. The source material for Platelets is plasma which may be obtained by whole...

  13. Platelet cytoskeleton and its hemostatic role.

    PubMed

    Cerecedo, Doris

    2013-12-01

    Upon vascular injury, platelets adhere to the exposed extracellular matrix, which triggers the platelet activation and aggregation to form a hemostatic plug to seal the wound. All of these events involve dramatic changes in shape because of the cytoskeleton reorganization. The versatility of the cytoskeleton's main elements depends on the biochemical nature of the elements, as well as on the associated proteins that confer multiple functions within the cell. The list of these associated proteins grows actively, increasing our knowledge concerning the complexity of platelet cytoskeleton machinery. The present review evidences the recently described platelet proteins that promote characteristic modifications in their cytoskeleton organization, with special focus on the dystrophin-glycoprotein complex. PMID:24030121

  14. Mapuche herbal medicine inhibits blood platelet aggregation.

    PubMed

    Falkenberg, Susan Skanderup; Tarnow, Inge; Guzman, Alfonso; Mølgaard, Per; Simonsen, Henrik Toft

    2012-01-01

    12 plant species traditionally used by the Mapuche people in Chile to treat wounds and inflammations have been evaluated for their direct blood platelet inhibition. Seven of the 12 tested plant species showed platelet inhibitory effect in sheep blood, and four of these were also able to inhibit the ADP- (5.0 μM) and collagen- (2.0 μg/mL) induced aggregations in human blood. These four species in respective extracts (in brackets) were Blechnum chilense (MeOH), Luma apiculata (H(2)O), Amomyrtus luma (DCM : MeOH 1 : 1) and Cestrum parqui (DCM : MeOH 1 : 1). The platelet aggregating inhibitory effects of A. luma (DCM : MeOH 1 : 1), and L. apiculata (H(2)O) were substantial and confirmed by inhibition of platelet surface activation markers. PMID:22028732

  15. Platelet concentrates: Balancing between efficacy and safety?

    PubMed

    Lozano, Miguel; Cid, Joan

    2016-01-01

    Platelet transfusions continue to be the mainstay to treat patients with quantitative and qualitative platelet disorders. Each year, about 10 millions of platelet transfusions are administered to patients worldwide with marked differences in usage between regions depending on socioeconomic development of the countries. Unfortunately, its use is associated to immune and non-immune side effects. Among the non-immune, bacterial contamination is still the major infectious risk. When bacterial culture methods are introduced for preventing bacterial septic reactions it has been found that this strategy reduce to one half the septic reactions, but do not eliminate completely that risk. To remove completely the risk, a new bacteria detection test at the time of issuance in the case of platelets stored for four or five days would be needed. Pathogen inactivation (PI) methods already in the market (based in the addition of amotosalen (A-L) or riboflavin (R-L) and the illumination with ultraviolet light) or under development (ultraviolet light C and agitation) have shown to be efficacious in the inactivation of bacteria and no cases of septic reactions associated to a pathogen-reduced product has been identified. However, it has been shown that PI technologies have measurable effects on platelet in vitro parameters and reduce the recovery and survival of treated platelets in vivo. Although these effects do not hamper the hemostatic capacity of treated platelets, an increased usage associated with PI technologies has been reported. This increase in utilization seems to be the toll to be paid if we want to completely eliminate the risk of bacterial sepsis in the recipients of platelet transfusion. PMID:27476010

  16. Stimulus-response coupling in platelets

    SciTech Connect

    Huang, E.M.

    1986-01-01

    To understand the mechanism of stimulus-response coupling in platelets, the potentiating effect of succinate and lithium on platelet activation was examined. The action of succinate was immediate; preincubation with succinate did not lead to desensitization. Succinate was comparable to ADP in lowering cAMP levels previously elevated by PGl/sub 2/. Since inhibition of cAMP is not a prerequisite for platelet activation, the mechanism of potentiation of succinate remains undefined. Lithium has also been shown to inhibit adenylate cyclase in PGl/sub 2/-pretreated platelets. Lithium, however, can also inhibit inositol phosphate (InsP) phosphatase and lead to an accumulation of InsP. In human platelets, lithium also enhanced the thrombin-induced accumulation of (/sup 3/H)inositol-labelled inositol trisphosphate (InsP/sub 3/), and inositol bisphosphate (InsP/sub 2/). One hour after thrombin addition, all 3 inositol phosphates returned to near basal levels. In the presence of lithium, while labelled InsP/sub 2/ and InsP/sub 3/ returned to their respective basal levels, the InsP level remained elevated, consistent with the known inhibitory effect of lithium on InsP phosphatase. In thrombin-stimulated platelets prelabeled with (/sup 32/P)phosphate, lithium led to a decrease in labelled phosphatidylinositol 4-phosphate (PtdIns4P) as well as an enhanced production of labelled lysophosphatidylinositol, suggesting multiple effects of lithium on platelet phosphoinositide metabolism. These observed effects, however, occurred too slowly to be the mechanism by which lithium potentiated agonist-induced platelet activation. To study the agonist-receptor interaction, the effect of the specific, high affinity thrombin inhibitor, hirudin, on thrombin-induced accumulation of (/sup 3/H)inositol-labelled inositol phosphates was studied.

  17. Colorectal tumors: scintigraphy with In-111 anti-CEA monoclonal antibody and correlation with surgical, histopathologic, and immunohistochemical findings

    SciTech Connect

    Abdel-Nabi, H.H.; Schwartz, A.N.; Goldfogel, G.; Ortman-Nabi, J.A.; Matsuoka, D.M.; Unger, M.W.; Wechter, D.G.

    1988-03-01

    A prospective clinical study of 17 patients with a histologic diagnosis of colorectal carcinoma proved at colonoscopy and surgery was performed with indium-111 anticarcinoembryonic-antigen (CEA) monoclonal antibody (MoAb), ZCE-025. MoAb scanning depicted nine of 16 primary colorectal carcinomas on planar scintigrams (true-positive findings = 56%) and ten of 16 lesions on single-photon emission computed tomography (SPECT) scans (true-positive findings = 62%). Liver metastases were detected in three of three patients, and lymph node metastases were detected in one of four patients. Immunohistochemical examination for CEA in resected colorectal cancer tissues demonstrated a positive correlation between MoAb imaging of primary lesions and cytoplasmic-stromal intracellular CEA distribution. There was no correlation between CEA serum levels and lesion detectability with MoAb scanning.

  18. The genetics of normal platelet reactivity.

    PubMed

    Kunicki, Thomas J; Nugent, Diane J

    2010-10-14

    Genetic and environmental factors contribute to a substantial variation in platelet function seen among normal persons. Candidate gene association studies represent a valiant effort to define the genetic component in an era where genetic tools were limited, but the single nucleotide polymorphisms identified in those studies need to be validated by more objective, comprehensive approaches, such as genome-wide association studies (GWASs) of quantitative functional traits in much larger cohorts of more carefully selected normal subjects. During the past year, platelet count and mean platelet volume, which indirectly affect platelet function, were the subjects of GWAS. The majority of the GWAS signals were located to noncoding regions, a consistent outcome of all GWAS to date, suggesting a major role for mechanisms that alter phenotype at the level of transcription or posttranscriptional modifications. Of 15 quantitative trait loci associated with mean platelet volume and platelet count, one located at 12q24 is also a risk locus for coronary artery disease. In most cases, the effect sizes of individual quantitative trait loci are admittedly small, but the results of these studies have led to new insight into regulators of hematopoiesis and megakaryopoiesis that would otherwise be unapparent and difficult to define. PMID:20610812

  19. Anti-platelet therapy: phosphodiesterase inhibitors

    PubMed Central

    Gresele, Paolo; Momi, Stefania; Falcinelli, Emanuela

    2011-01-01

    Inhibition of platelet aggregation can be achieved either by the blockade of membrane receptors or by interaction with intracellular signalling pathways. Cyclic adenosine 3′,5′-monophosphate (cAMP) and cyclic guanosine 3′,5′-monophosphate (cGMP) are two critical intracellular second messengers provided with strong inhibitory activity on fundamental platelet functions. Phosphodiesterases (PDEs), by catalysing the hydrolysis of cAMP and cGMP, limit the intracellular levels of cyclic nucleotides, thus regulating platelet function. The inhibition of PDEs may therefore exert a strong platelet inhibitory effect. Platelets possess three PDE isoforms (PDE2, PDE3 and PDE5), with different selectivity for cAMP and cGMP. Several nonselective or isoenzyme-selective PDE inhibitors have been developed, and some of them have entered clinical use as antiplatelet agents. This review focuses on the effect of PDE2, PDE3 and PDE5 inhibitors on platelet function and on the evidence for an antithrombotic action of some of them, and in particular of dipyridamole and cilostazol. PMID:21649691

  20. STIM and Orai in platelet function.

    PubMed

    Varga-Szabo, David; Braun, Attila; Nieswandt, Bernhard

    2011-09-01

    Physiological platelet activation and thrombus formation are essential to stop bleeding in case of vascular injury, whereas inadequate triggering of the same process in diseased vessels can lead to fatal thromboembolism and tissue ischemia of vital organs. A central step in platelet activation is agonist-induced elevation of the intracellular Ca(2+) concentration. This happens on the one hand through the release of Ca(2+) from intracellular stores and on the other hand through Ca(2+) influx from the extracellular space. In platelets, the major Ca(2+) influx pathway is the so-called store operated Ca(2+) entry (SOCE), induced by store depletion. Studies in the last five years discovered the molecular background of platelet SOCE. Stromal interaction molecule 1 (STIM1) and Orai1, two so far unknown molecules, got in the focus of research. STIM1 was found to be the Ca(2+) sensor in the endoplasmic reticulum (ER) membrane, whereas Orai1 was identified as the major store operated Ca(2+) (SOC) channel in the plasma membrane. These two molecules and their role in platelet function and thrombus formation are the topic of the present review with a special focus on apoptosis and apoptosis-like processes in platelet physiology. PMID:21616531

  1. Platelet dysfunction in vincristine treated patients.

    PubMed

    Steinherz, P G; Miller, D R; Hilgartner, M W; Schmalzer, E A

    1976-03-01

    Recent revival of interest in the use of vincristine (VCR) for the treatment of idiopathic thrombocytopenic purpura prompted us to evaluate the platelet function of our patients on VCR. Eighteen patients with acute lymphoblastic leukaemia (ALL) in remission, and nine children with solid tumours were studied on 80 occasions at different time intervals after their last VCR dose. A mildly elevated threshold for epinephrine-induced second phase aggregation and a delay in the onset of collagen-induced aggregation was found in patients with ALL not on VCR. Vincristine induced unobtainable second phase aggregation to epinephrine in 67%, 38%, 30% and to ADP in 53%, 13%, 33% of the patients 1 week, 2-3 weeks and 4 weeks respectively after administration. The thrombocytopathy was relative, not absolute, since collagen induced aggregation at all times. Platelet counts, uptake and release of serotonin, bleeding times, clot retractions and release of platelet factor 3 were normal. Platelet adhesion was abnormal in five of 12 patients tested. In vitro platelets are a hundred-fold less sensitive to VCR than in vivo. Cyclic adenosine monophosphate, cyclic guanosine monophosphate and dimethylsulfoxide do not protect platelets from VCR. The exact mechanism by which VCR abolishes second phase aggregation in patients is uncertain. Because of VCR's narrow therapeutic index between thrombocytopenia and thrombocythaemia, the use of VCR should be reserved for life-threatening haematologic disorders when treating non-malignant conditions. PMID:175822

  2. Treatment of osteochondral injuries with platelet gel

    PubMed Central

    Danieli, Marcus Vinicius; da Rosa Pereira, Hamilton; de Sá Carneiro, Carlos Augusto; Felisbino, Sérgio Luiz; Deffune, Elenice

    2014-01-01

    OBJECTIVES: Treatments for injured articular cartilage have not advanced to the point that efficient regeneration is possible. However, there has been an increase in the use of platelet-rich plasma for the treatment of several orthopedic disorders, including chondral injuries. Our hypothesis is that the treatment of chondral injuries with platelet gel results in higher-quality repair tissue after 180 days compared with chondral injuries not treated with gel. METHODS: A controlled experimental laboratory study was performed on 30 male rabbits to evaluate osteochondral injury repair after treatment with or without platelet gel. Osteochondral injuries were surgically induced in both knees of each rabbit at the medial femoral condyle. The left knee injury was filled with the platelet gel, and the right knee was not treated. Microscopic analysis of both knee samples was performed after 180 days using a histological grading scale. RESULTS: The only histological evaluation criterion that was not significantly different between treatments was metachromasia. The group that was treated with platelet gel exhibited superior results in all other criteria (cell morphology, surface regularity, chondral thickness and repair tissue integration) and in the total score. CONCLUSION: The repair tissue was histologically superior after 180 days in the study group treated with platelet gel compared with the group of untreated injuries. PMID:25518022

  3. Effects of irradiation on platelet function

    SciTech Connect

    Rock, G.; Adams, G.A.; Labow, R.S.

    1988-09-01

    Current medical practice involves the irradiation of blood components, including platelet concentrates, before their administration to patients with severe immunosuppression. The authors studied the effect of irradiation on in vitro platelet function and the leaching of plasticizers from the bag, both immediately and after 5 days of storage. The platelet count, white cell count, pH, glucose, lactate, platelet aggregation and release reaction, and serotonin uptake were not altered by the irradiation of random-donor or apheresis units with 2000 rads carried out at 0 and 24 hours and 5 days after collection. The leaching of di(2-ethylhexyl)phthalate from the plastic bags followed by the conversion to mono(2-ethylhexyl)phthalate was not increased by irradiation. Therefore, it is possible to irradiate platelet concentrates on the day of collection and subsequently store them for at least 5 days while maintaining in vitro function. This procedure could have considerable benefit for blood banks involved in the provision of many platelet products.

  4. The platelet serotonin-release assay.

    PubMed

    Warkentin, Theodore E; Arnold, Donald M; Nazi, Ishac; Kelton, John G

    2015-06-01

    Few laboratory tests are as clinically useful as The platelet serotonin-release assay (SRA): a positive SRA in the appropriate clinical context is virtually diagnostic of heparin-induced thrombocytopenia (HIT), a life- and limb-threatening prothrombotic disorder caused by anti-platelet factor 4 (PF4)/heparin antibodies that activate platelets, thereby triggering serotonin-release. The SRA's performance characteristics include high sensitivity and specificity, although caveats include indeterminate reaction profiles (observed in ∼4% of test sera) and potential for false-positive reactions. As only a subset of anti-PF4/heparin antibodies detectable by enzyme-immunoassay (EIA) are additionally platelet-activating, the SRA has far greater diagnostic specificity than the EIA. However, requiring a positive EIA, either as an initial screening test or as an SRA adjunct, will reduce risk of a false-positive SRA (since a negative EIA in a patient with a "positive" SRA should prompt critical evaluation of the SRA reaction profile). The SRA also provides useful information on whether a HIT serum produces strong platelet activation even in the absence of heparin: such heparin-"independent" platelet activation is a marker of unusually severe HIT, including delayed-onset HIT and severe HIT complicated by consumptive coagulopathy with risk for microvascular thrombosis. PMID:25775976

  5. Use of mean platelet component to measure platelet activation on the ADVIA 120 haematology system.

    PubMed

    Macey, M G; Carty, E; Webb, L; Chapman, E S; Zelmanovic, D; Okrongly, D; Rampton, D S; Newland, A C

    1999-10-15

    Platelet activation results in changes in a number of cell surface molecules including an increase in P-Selectin (CD62P) that may be rapidly and conveniently measured by immunofluorescent flow cytometry. The ADVIA 120 (Bayer) is a new system that facilitates more accurate measurement of platelet volume and in addition provides an approximate measure of the mean refractive index (RI) of the platelets reported as mean platelet component (MPC) concentration. We were interested to determine whether changes in MPC might reflect changes in platelet activation status. To investigate this, the platelet CD62P expression, determined by flow cytometry, and change in MPC, measured on the ADVIA 120 system, was first examined in vitro after stimulation of EDTA anticoagulated whole blood with submaximal concentrations of bovine thrombin in the presence or absence of the thromboxane synthase inhibitor, Ridogrel. Thrombin produced a dose-dependent increase in platelet CD62P expression and a decrease in MPC that could be inhibited by Ridogrel at physiological concentrations. In the second set of experiments, blood from 20 normal controls was collected into both EDTA and sodium citrate (SC) anticoagulants. Within 30 min of venesection and again at 3 h post-venesection after storage at room temperature, the platelet MPC and CD62P expression were determined. Platelets in all samples with both anticoagulants showed very low levels of CD62P expression when first analysed. At 3 h there was a small increase in CD62P expression on platelets in whole blood anticoagulated with SC, but a significant (P < 0.001) increase was observed on platelets anti-coagulated with EDTA. A negative correlation was found between the change in MPC of the platelets and the increase in the mean fluorescence intensity (MFI) (r = -0.69, P < 0.001, n = 20) and the percentage (r = -0.72, P < 0.001, n = 20) of CD62P positive platelets at 3 h in blood anticoagulated with EDTA. We conclude that a reduction in MPC as

  6. A New Ibuprofen Derivative Inhibits Platelet Aggregation and ROS Mediated Platelet Apoptosis

    PubMed Central

    Hemshekhar, Mahadevappa; Paul, Manoj; Thushara, Ram M.; Sundaram, Mahalingam S.; Swaroop, Toreshettahally R.; Mohan, Chakrabhavi D.; Basappa; Sadashiva, Marilinganadoddi P.; Kemparaju, Kempaiah; Girish, Kesturu S.; Rangappa, Kanchugarakoppal S.

    2014-01-01

    Thrombocytopenia is a serious issue connected with the pathogenesis of several human diseases including chronic inflammation, arthritis, Alzheimer's disease, cardiovascular diseases (CVDs) and other oxidative stress-associated pathologies. The indiscriminate use of antibiotics and other biological drugs are reported to result in thrombocytopenia, which is often neglected during the treatment regime. In addition, augmented oxidative stress induced by drugs and pathological conditions has also been shown to induce thrombocytopenia, which seems to be the most obvious consequence of elevated rate of platelet apoptosis. Thus, blocking oxidative stress-induced platelet apoptosis would be of prime importance in order to negotiate thrombocytopenia and associated human pathologies. The current study presents the synthesis and platelet protective nature of novel ibuprofen derivatives. The potent anti-oxidant ibuprofen derivative 4f was selected for the study and the platelet protective efficacy and platelet aggregation inhibitory property has been demonstrated. The compound 4f dose dependently mitigates the oxidative stress-induced platelet apoptosis in both platelet rich plasma and washed platelets. The platelet protective nature of compound 4f was determined by assessing various apoptotic markers such as ROS generation, cytosolic Ca2+ levels, PS externalization, cytochrome C translocation, Caspase activation, mitochondrial membrane depolarization, cytotoxicity, LDH leakage and tyrosine phosphorylation of cytosolic proteins. Furthermore, compound 4f dose dependently ameliorated agonist induced platelet aggregation. Therefore, compound 4f can be estimated as a potential candidate in the treatment regime of pathological disorders associated with platelet activation and apoptosis. In addition, compound 4f can be used as an auxiliary therapeutic agent in pathologies associated with thrombocytopenia. PMID:25238069

  7. An Incidental Detection of Popliteal Vein Aneurysm during Labeled Leukocyte Scintigraphy

    PubMed Central

    Hassan, H. Abu.; Nazri, M.; Azman, R. R.

    2012-01-01

    Technetium (99mTc) exametazime (hexamethylpropyleneamine oxime, HMPAO) labeled leukocyte scintigraphy is mainly used to exclude occult infection in our institution. On review of previously published article, no case of popliteal venous aneurysm was ever diagnosed and detected on labeled leukocyte scintigraphy. We present a rare case of popliteal venous aneurysm which was detected on labeled leukocyte scintigraphy and was further confirmed with single-photon emission computed tomography and computed tomography fusion. PMID:23372443

  8. Platelet--arterial synthetic graft interaction and its modification

    SciTech Connect

    Callow, A.D.; Connolly, R.; O'Donnell, T.F. Jr.; Gembarowicz, R.; Keough, E.; Ramberg-Laskaris, K.; Valeri, C.R.

    1982-11-01

    We compared the in vivo platelet reactivity of two commonly used clinical grafts, Dacron and expanded polytetrafluoroethylene (PTFE), with that of a control autogenous artery graft and assessed whether platelet reactivity was modified by the platelet-antiaggregating agent prostacyclin (PGI2) (epoprostenol). Grafts were randomly placed into the carotid arteries of 21 baboons. Platelets labeled with /sup 111/In were infused within one hour after implantation graft for gamma camera scanning of platelet uptake. The accumulation of platelets on Dacron grafts began almost immediately after injection and reached a peak after one to two hours. The PTFE and control autogenous artery grafts accumulated comparable small amounts of platelets. Prostacyclin was then infused in a second series of baboons with Dacron grafts, at a rate of 150 to 200 ng/kg/min. It prevented the usual platelet uptake when administered concomitant with graft implantation and reduced previously established platelet activity.

  9. Preparation of washed platelets from non-anticoagulated human blood.

    PubMed

    Bowry, S K; Müller-Berghaus, G

    1986-09-15

    Sodium citrate is almost always used to anticoagulate blood for the preparation of washed platelet suspensions. Several adverse effects of citrate on platelet functional responses have been reported. We investigated the extent of activation of platelets and plasmatic coagulation during the preparation of washed platelets from human blood to which no anticoagulant was added. Washed platelets from native blood (PNB) were prepared by passing freshly-drawn human blood rapidly through a mixed Sephadex G-25/G-50 column to remove divalent cations. Gel-filtered blood (GFB), diluted by the elution medium containing 0.35% albumin and 2U/ml apyrase, was obtained within 5 minutes of venepuncture. Using CaCl2, the GFB was found to contain a mean of 1.65 X 10 mM calcium. Fibrinopeptide A measurements indicated less activation of plasmatic coagulation in GFB than in citrated blood. Measurements of beta-thromboglobulin and platelet factor 4 during the various stages of the preparation of PNB showed no platelet activation. No platelet aggregates, as measured by the platelet aggregate ratio method, were observed in GFB. Transmission electron microscopy showed intact discoid platelets similar to those in platelet-rich plasma. The reduced activation of platelets and of plasmatic coagulation was due to the more effective removal of calcium ions from the blood by gel filtration than chelation by citrate. PNB may thus provide a model for studying the requirements for calcium in platelet function in the absence of any citrate-platelet interactions. PMID:2945282

  10. Resveratrol preserves the function of human platelets stored for transfusion.

    PubMed

    Lannan, Katie L; Refaai, Majed A; Ture, Sara K; Morrell, Craig N; Blumberg, Neil; Phipps, Richard P; Spinelli, Sherry L

    2016-03-01

    Stored platelets undergo biochemical, structural and functional changes that lead to decreased efficacy and safety of platelet transfusions. Not only do platelets acquire markers of activation during storage, but they also fail to respond normally to agonists post-storage. We hypothesized that resveratrol, a cardioprotective antioxidant, could act as a novel platelet storage additive to safely prevent unwanted platelet activation during storage, while simultaneously preserving normal haemostatic function. Human platelets treated with resveratrol and stored for 5 d released less thromboxane B2 and prostaglandin E2 compared to control platelets. Resveratrol preserved the ability of platelets to aggregate, spread and respond to thrombin, suggesting an improved ability to activate post-storage. Utilizing an in vitro model of transfusion and thromboelastography, clot strength was improved with resveratrol treatment compared to conventionally stored platelets. The mechanism of resveratrol's beneficial actions on stored platelets was partly mediated through decreased platelet apoptosis in storage, resulting in a longer half-life following transfusion. Lastly, an in vivo mouse model of transfusion demonstrated that stored platelets are prothrombotic and that resveratrol delayed vessel occlusion time to a level similar to transfusion with fresh platelets. We show resveratrol has a dual ability to reduce unwanted platelet activation during storage, while preserving critical haemostatic function. PMID:26683619

  11. Platelet Inhibition by Nitrite Is Dependent on Erythrocytes and Deoxygenation

    PubMed Central

    Srihirun, Sirada; Sriwantana, Thanaporn; Unchern, Supeenun; Kittikool, Dusadee; Noulsri, Egarit; Pattanapanyasat, Kovit; Fucharoen, Suthat; Piknova, Barbora; Schechter, Alan N.; Sibmooh, Nathawut

    2012-01-01

    Background Nitrite is a nitric oxide (NO) metabolite in tissues and blood, which can be converted to NO under hypoxia to facilitate tissue perfusion. Although nitrite is known to cause vasodilation following its reduction to NO, the effect of nitrite on platelet activity remains unclear. In this study, the effect of nitrite and nitrite+erythrocytes, with and without deoxygenation, on platelet activity was investigated. Methodology/Finding Platelet aggregation was studied in platelet-rich plasma (PRP) and PRP+erythrocytes by turbidimetric and impedance aggregometry, respectively. In PRP, DEANONOate inhibited platelet aggregation induced by ADP while nitrite had no effect on platelets. In PRP+erythrocytes, the inhibitory effect of DEANONOate on platelets decreased whereas nitrite at physiologic concentration (0.1 µM) inhibited platelet aggregation and ATP release. The effect of nitrite+erythrocytes on platelets was abrogated by C-PTIO (a membrane-impermeable NO scavenger), suggesting an NO-mediated action. Furthermore, deoxygenation enhanced the effect of nitrite as observed from a decrease of P-selectin expression and increase of the cGMP levels in platelets. The ADP-induced platelet aggregation in whole blood showed inverse correlations with the nitrite levels in whole blood and erythrocytes. Conclusion Nitrite alone at physiological levels has no effect on platelets in plasma. Nitrite in the presence of erythrocytes inhibits platelets through its reduction to NO, which is promoted by deoxygenation. Nitrite may have role in modulating platelet activity in the circulation, especially during hypoxia. PMID:22276188

  12. Geometric complexity identifies platelet activation in familial hypercholesterolemic patients.

    PubMed

    Bianciardi, Giorgio; Aglianò, Margherita; Volpi, Nila; Stefanutti, Claudia

    2015-06-01

    Familial hypercholesterolemia (FH), a genetic disease, is associated with a severe incidence of athero-thrombotic events, related, also, to platelet hyperreactivity. A plethora of methods have been proposed to identify those activated circulating platelets, none of these has proved really effective. We need efficient methods to identify the circulating platelet status in order to follow the patients after therapeutic procedures. We propose the use of computerized fractal analysis for an objective characterization of the complexity of circulating platelet shapes observed by means of transmission electron microscopy in order to characterize the in vivo hyperactivated platelets of familial hypercholesterolemic patients, distinguishing them from the in vivo resting platelets of healthy individuals. Platelet boundaries were extracted by means of automatically image analysis. Geometric complexity (fractal dimension, D) by box counting was automatically calculated. The platelet boundary observed by electron microscopy is fractal, the shape of the circulating platelets is more complex in FH (n = 6) than healthy subjects (n = 5, P < 0.01), with 100% correct classification in selected individuals. In vitro activated platelets from healthy subjects show an analogous increase of D. The observed high D in the platelet boundary in FH originates from the in vivo platelet activation. Computerized fractal analysis of platelet shape observed by transmission electron microscopy can provide accurate, quantitative data to study platelet activation in familial hypercholesterolemia and after administration of drugs or other therapeutic procedures. PMID:25877374

  13. Procoagulant activity on platelets adhered to collagen or plasma clot.

    PubMed

    Ilveskero, S; Siljander, P; Lassila, R

    2001-04-01

    In a new 2-stage assay of platelet procoagulant activity (PCA), we first subjected gel-filtered platelets to adhesion on collagen (as a model of primary hemostasis) or plasma clots (as a model of preformed thrombus) for 30 minutes, and then the adherent platelets were supplemented with pooled, reptilase-treated, diluted plasma. Defibrinated plasma provided coagulation factors for assembly on platelet membranes without uncontrolled binding of thrombin to fibrin(ogen). Platelet adhesion to both surfaces showed modest individual variation, which increased at platelet densities that allowed aggregation. However, adhesion-induced PCA varied individually and surface-independently >3-fold, suggesting a uniform platelet procoagulant mechanism. Permanently adhered platelets showed markedly enhanced PCA when compared with the platelet pool in suspension, even after strong activation. The rate of thrombin generation induced by clot-adherent platelets was markedly faster than on collagen-adherent platelets during the initial phase of coagulation, whereas collagen-induced PCA proceeded slowly, strongly promoted by tissue thromboplastin. Therefore at 10 minutes, after adjustment for adhered platelets, collagen supported soluble thrombin formation as much as 5 times that of the thrombin-retaining clots. Activation of platelets by their firm adhesion was accompanied by formation of microparticles, representing about one third of the total soluble PCA. Collagen-adhered platelets provide soluble thrombin and microparticles, whereas the preformed clot serves to localize and accelerate hemostasis at the injury site, with the contribution of retained thrombin and microparticles. PMID:11304482

  14. Nitric oxide and platelet energy metabolism.

    PubMed

    Tomasiak, Marian; Stelmach, Halina; Rusak, Tomasz; Wysocka, Jolanta

    2004-01-01

    This study was undertaken to determine whether nitric oxide (NO) can affect platelet responses through the inhibition of energy production. It was found that NO donors: S-nitroso-N-acetylpenicyllamine, SNAP, (5-50 microM) and sodium nitroprusside, SNP, (5-100 microM) inhibited collagen- and ADP-induced aggregation of porcine platelets. The corresponding IC50 values for SNAP and SNP varied from 5 to 30 microM and from 9 to 75 microM, respectively. Collagen- and thrombin-induced platelet secretion was inhibited by SNAP (IC50 = 50 microM) and by SNP (IC50 = 100 microM). SNAP (20-100 microM), SNP (10-200 microM) and collagen (20 microg/ml) stimulated glycolysis in intact platelets. The degree of glycolysis stimulation exerted by NO donors was similar to that produced by respiratory chain inhibitors (cyanide and antimycin A) or uncouplers (2,4-dinitrophenol). Neither the NO donors nor the respiratory chain blockers affected glycolysis in platelet homogenate. SNAP (20-100 microM) and SNP (50-200 microM) inhibited oxygen consumption by platelets. The effect of SNP and SNAP on glycolysis and respiration was not reduced by 1H-[1,2,4]oxadiazolo-[4,3-a]quinoxalin-1-one, a selective inhibitor of NO-stimulated guanylate cyclase. SNAP (5-100 microM) and SNP (10-300 microM) inhibited the activity of platelet cytochrome oxidase and had no effect on NADH:ubiquinone oxidoreductase and succinate dehydrogenase. Blocking of the mitochondrial energy production by antimycin A slightly affected collagen-evoked aggregation and strongly inhibited platelet secretion. The results indicate that: 1) in porcine platelets NO is able to diminish mitochondrial energy production through the inhibition of cytochrome oxidase, 2) the inhibitory effect of NO on platelet secretion (but not aggregation) can be attributed to the reduction of mitochondrial energy production. PMID:15448739

  15. Platelet Consumption by Arterial Prostheses: The Effects of Endothelialization and Pharmacologic Inhibition of Platelet Function

    PubMed Central

    Harker, Laurence A.; Slichter, Sherrill J.; Sauvage, Lester R.

    1977-01-01

    The thrombogenic mechanism of arterial grafts has been studied by determining the relative utilization of platelets, fibrinogen and plasminogen by human arterial prostheses, and by direct examination of arterial grafts in a baboon model. Forty-one survival and turnover measurements of 51Crplatelets, 131I-fibrinogen and 125I-plasminogen in ten patients with aortofemoral knitted Dacron prostheses demonstrated platelet consumption after graft placement (platelet survival 4.2 days ± 0.5 and turnover 68,000 plat/ul/day ±10,000 compared with 8.2 days ± 0.3 and 35,000 plat/ul/day ± 5,000 respectively for control subjects with stable vascular disease, p < 0.01). In vitro platelet function test results were normal. Platelet consumption was interrupted by dipyridamole or a combination of dipyridamole and acetylsalicylic acid, and platelet survival normalized spontaneously during nine months postoperatively. No significantly increased consumption of fibrinogen or plasminogen was found in these patients with arterial grafts. Placement of impervious knitted Dacron velour aortic grafts in baboons reproduced platelet consumption that progressively normalized over six weeks postoperatively. Platelet survival measurements correlated directly with endothelial cell coverage of the graft luminal surface in these animals implying that endothelialization of the graft surface was also occurring postoperatively in patients. ImagesFig. 4.Fig. 5. PMID:411428

  16. CLEC-2 expression is maintained on activated platelets and on platelet microparticles.

    PubMed

    Gitz, Eelo; Pollitt, Alice Y; Gitz-Francois, Jerney J; Alshehri, Osama; Mori, Jun; Montague, Samantha; Nash, Gerard B; Douglas, Michael R; Gardiner, Elizabeth E; Andrews, Robert K; Buckley, Christopher D; Harrison, Paul; Watson, Steve P

    2014-10-01

    The C-type lectin-like receptor CLEC-2 mediates platelet activation through a hem-immunoreceptor tyrosine-based activation motif (hemITAM). CLEC-2 initiates a Src- and Syk-dependent signaling cascade that is closely related to that of the 2 platelet ITAM receptors: glycoprotein (GP)VI and FcγRIIa. Activation of either of the ITAM receptors induces shedding of GPVI and proteolysis of the ITAM domain in FcγRIIa. In the present study, we generated monoclonal antibodies against human CLEC-2 and used these to measure CLEC-2 expression on resting and stimulated platelets and on other hematopoietic cells. We show that CLEC-2 is restricted to platelets with an average copy number of ∼2000 per cell and that activation of CLEC-2 induces proteolytic cleavage of GPVI and FcγRIIa but not of itself. We further show that CLEC-2 and GPVI are expressed on CD41+ microparticles in megakaryocyte cultures and in platelet-rich plasma, which are predominantly derived from megakaryocytes in healthy donors, whereas microparticles derived from activated platelets only express CLEC-2. Patients with rheumatoid arthritis, an inflammatory disease associated with increased microparticle production, had raised plasma levels of microparticles that expressed CLEC-2 but not GPVI. Thus, CLEC-2, unlike platelet ITAM receptors, is not regulated by proteolysis and can be used to monitor platelet-derived microparticles. PMID:25150298

  17. Platelets and atherogenesis: Platelet anti-aggregation activity and endothelial protection from tomatoes (Solanum lycopersicum L.)

    PubMed Central

    PALOMO, IVÁN; FUENTES, EDUARDO; PADRÓ, TERESA; BADIMON, LINA

    2012-01-01

    In recent years, it has been shown that platelets are not only involved in the arterial thrombotic process, but also that they play an active role in the inflammatory process of atherogenesis from the beginning. The interaction between platelets and endothelial cells occurs in two manners: activated platelets unite with intact endothelial cells, or platelets in resting adhere to activated endothelium. In this context, inhibition of the platelet function (adhesion/aggregation) could contribute to the prevention of atherothrombosis, the leading cause of cardiovascular morbidity. This can be achieved with antiplatelet agents. However, at the public health level, the level of primary prevention, a healthy diet has also been shown to exert beneficial effects. Among those elements of a healthy diet, the consumption of tomatoes (Solanum lycopersicum L.) stands out for its effect on platelet anti-aggregation activity and endothelial protection, which may be beneficial for cardiovascular health. This article briefly discusses the involvement of platelets in atherogenesis and the possible mechanisms of action provided by tomatoes for platelet anti-aggregation activity and endothelial protection. PMID:22969932

  18. Bone scintigraphy of hip joint effusions in children

    SciTech Connect

    Kloiber, R.; Pavlosky, W.; Portner, O.; Gartke, K.

    1983-05-01

    Thirty-eight children with hip pain of acute onset were studied by bone scintigraphy. Nine patients had diminished radiotracer deposition involving the entire proximal femoral ossification center. This could be related to infarction or compression of blood supply by a tense joint effusion. Eight of these patients had joint aspiration confirming the presence of an effusion. Five patients had follow-up studies after aspiration, and femoral-head uptake reverted to normal in all but one which subsequently proved to be infarcted. A photopenic zone was seen on blood pool images in 10 patients, many of whom were also aspirated of fluid. Bone scintigraphy is useful in the diagnosis of joint effusions and can give information as to the state of perfusion of the femoral head. Follow-up studies after aspiration can differentiate infarction from reversible ischemia.

  19. [Diagnostic benefits of adrenocortical scintigraphy in hepatic adrenal rest tumor].

    PubMed

    Ishida, Kosuke; Horii, Rika; Yamashita, Tatsuya; Arai, Kuniaki; Yamashita, Taro; Kagaya, Takashi; Sakai, Yoshio; Mizukoshi, Eishiro; Honda, Masao; Kaneko, Shuichi

    2014-10-01

    An 81-year-old female was referred to our hospital for the examination of an S7 liver tumor. The tumor was suspected to be a hepatic adrenal rest tumor (HART) based on ultrasonography, dynamic CT, Gd-EOB-DTPA-enhanced MRI, and CT during abdominal angiography. After various hormonal tests, the tumor was confirmed as hormonally non-functional. The diagnosis of HART was confirmed based on (131)I-adosterol accumulation in the tumor by adrenocortical scintigraphy. The resected tumor was histologically compatible with HART, and it may have been able to produce cortisol based on the immunohistochemical findings of various adrenocortical hormone metabolic enzymes. Adrenocortical scintigraphy may thus be useful in diagnosing HART. PMID:25283230

  20. Role of scintigraphy in focally abnormal sonograms of fatty livers

    SciTech Connect

    Lisbona, R.; Mishkin, S.; Derbekyan, V.; Novales-Diaz, J.A.; Roy, A.; Sanders, L.

    1988-06-01

    Fatty infiltration of the liver may cause a range of focal abnormalities on hepatic sonography which may simulate hepatic nodular lesions. Discrete deposits of fat or islands of normal tissue which are uninvolved by fatty infiltration may stand out as potential space-occupying lesions on the sonograms. Twelve patients with such focally abnormal ultrasound images were referred for liver scintigraphy with /sup 133/Xe and /sup 99m/Tc colloidal SPECT studies to clarify the issue. These examinations helped identify, in nine of 12 patients, the innocent nature of the sonographic abnormalities which were simply related to the fat deposition process. Further, (/sup 99m/Tc)RBC scans defined the additional pathologic process in three patients in whom actual space-occupying lesions were indeed present in the liver. Scintigraphy has an important role to play in the understanding of focal hepatic ultrasound abnormalities particularly in unsuspected hepatic steatosis.

  1. Activated platelet chemiluminescence and presence of CD45+ platelets in patients with acute myocardial infarction.

    PubMed

    Gabbasov, Zufar; Ivanova, Oxana; Kogan-Yasny, Victor; Ryzhkova, Evgeniya; Saburova, Olga; Vorobyeva, Inna; Vasilieva, Elena

    2014-01-01

    It has been found that in 15% of acute myocardial infarction patients' platelets generate reactive oxygen species that can be detected with luminol-enhanced chemiluminescence of platelet-rich plasma within 8-10 days after acute myocardial infarction. This increase in generate reactive oxygen species production coincides with the emergence of CD45(+) platelets. The ability of platelets to carry surface leukocyte antigen implies their participation in exchange of specific proteins in the course of acute myocardial infarction. Future studies of CD45(+) platelets in peripheral blood of acute myocardial infarction patients in association with generate reactive oxygen species production may provide a new insight into the complex mechanisms of cell-cell interactions associated with acute myocardial infarction. PMID:24102264

  2. Spurious automated platelet count. Enumeration of yeast forms as platelets by the cell-DYN 4000.

    PubMed

    Latif, Shahnila; Veillon, Diana M; Brown, Donald; Kaltenbach, Jenny; Curry, Sherry; Linscott, Andrea J; Oberle, Arnold; Cotelingam, James D

    2003-12-01

    We recently encountered a patient with thrombocytopenia secondary to multiple drug therapy, disseminated prostatic adenocarcinoma, and sepsis who had a sudden decrease in his platelet count as enumerated by the Cell-DYN 4000 hematology analyzer (Abbott Diagnostics, Santa Clara, CA). A manual platelet count performed thereafter was even lower. The etiology of the spurious platelet count was clarified when numerous yeast forms were observed on routine microscopy of the peripheral blood smear. Subsequently, these organisms were identified as Candida glabrata from a positive blood culture (BACTEC 9240, Becton Dickinson, Cockeysville, MD). To our knowledge, this is the first report of spurious enumeration of yeast forms as platelets in an automated hematology system. The principle underlying platelet enumeration by the Cell-DYN 4000 system and other hematology analyzers and the value of microscopy on peripheral smears with unexpected CBC count results are discussed. PMID:14671977

  3. Hematopoietic transcription factor mutations and inherited platelet dysfunction

    PubMed Central

    Songdej, Natthapol

    2015-01-01

    The molecular and genetic mechanisms in most patients with inherited platelet dysfunction are unknown. There is increasing evidence that mutations in hematopoietic transcription factors are major players in the pathogenesis of defective megakaryopoiesis and platelet dysfunction in patients with inherited platelet disorders. These hematopoietic transcription factors include RUNX1, FLI1, GATA-1, and GFI1B. Mutations involving these transcription factors affect diverse aspects of platelet production and function at the genetic and molecular levels, culminating in clinical manifestations of thrombocytopenia and platelet dysfunction. This review focuses on these hematopoietic transcription factors in the pathobiology of inherited platelet dysfunction. PMID:26097739

  4. Platelets promote osteosarcoma cell growth through activation of the platelet-derived growth factor receptor-Akt signaling axis

    PubMed Central

    Takagi, Satoshi; Takemoto, Ai; Takami, Miho; Oh-hara, Tomoko; Fujita, Naoya

    2014-01-01

    The interactions of tumor cells with platelets contribute to the progression of tumor malignancy, and the expression levels of platelet aggregation-inducing factors positively correlate with the metastatic potential of osteosarcoma cells. However, it is unclear how tumor-platelet interaction contributes to the proliferation of osteosarcomas. We report here that osteosarcoma-platelet interactions induce the release of platelet-derived growth factor (PDGF) from platelets, which promotes the proliferation of osteosarcomas. Co-culture of platelets with MG63 or HOS osteosarcoma cells, which could induce platelet aggregation, enhanced the proliferation of each cell line in vitro. Analysis of phospho-antibody arrays revealed that co-culture of MG63 cells with platelets induced the phosphorylation of platelet derived growth factor receptor (PDGFR) and Akt. The addition of supernatants of osteosarcoma-platelet reactants also increased the growth of MG63 and HOS cells as well as the level of phosphorylated-PDGFR and -Akt. Sunitinib or LY294002, but not erlotinib, significantly inhibited the platelet-induced proliferation of osteosarcoma cells, indicating that PDGF released from platelets plays an important role in the proliferation of osteosarcomas by activating the PDGFR and then Akt. Our results suggest that inhibitors that specifically target osteosarcoma-platelet interactions may eradicate osteosarcomas. PMID:24974736

  5. Platelet Activation Test in Unprocessed Blood (Pac-t-UB) to Monitor Platelet Concentrates and Whole Blood of Thrombocytopenic Patients

    PubMed Central

    Roest, Mark; van Holten, Thijs C.; Fleurke, Ger-Jan; Remijn, Jasper A.

    2013-01-01

    Summary Background Platelet concentrate transfusion is the standard treatment for hemato-oncology patients to compensate for thrombocytopenia. We have developed a novel platelet activation test in anticoagulated unprocessed blood (pac-t-UB) to determine platelet function in platelet concentrates and in blood of thrombocytopenic patients. Methods We have measured platelet activity in a platelet concentrate and in anticoagulated unprocessed blood of a post-transfusion thrombocytopenic patient. Results Our data show time-dependent platelet activation by GPVI agonist (collagen related peptide; CRP), PAR-1 agonist (SFLLRN), P2Y12 agonist (ADP), and thromboxane receptor agonist (U46619) in a platelet concentrate. Furthermore, pac-t-UB showed time-dependent platelet activation in unprocessed blood of a post-transfusion patient with thrombocytopenia. Testing platelet function by different agonists in relation to storage show that 3-day-old platelet concentrates are still reactive to the studied agonists. This reactivity rapidly drops for each agonists during longer storage. Discussion Pac-t-UB is a novel tool to estimate platelet function by different agonists in platelet concentrates and in unprocessed blood of thrombocytopenic patients. In the near future, we will validate whether pac-t-UB is an adequate test to monitor the quality of platelet concentrates and whether pac-t-UB predicts the bleeding risk of transfused thrombocytopenic patients. PMID:23652405

  6. Comparative analysis of human ex vivo-generated platelets vs megakaryocyte-generated platelets in mice: a cautionary tale.

    PubMed

    Wang, Yuhuan; Hayes, Vincent; Jarocha, Danuta; Sim, Xiuli; Harper, Dawn C; Fuentes, Rudy; Sullivan, Spencer K; Gadue, Paul; Chou, Stella T; Torok-Storb, Beverly J; Marks, Michael S; French, Deborah L; Poncz, Mortimer

    2015-06-01

    Thrombopoiesis is the process by which megakaryocytes release platelets that circulate as uniform small, disc-shaped anucleate cytoplasmic fragments with critical roles in hemostasis and related biology. The exact mechanism of thrombopoiesis and the maturation pathways of platelets released into the circulation remain incompletely understood. We showed that ex vivo-generated murine megakaryocytes infused into mice release platelets within the pulmonary vasculature. Here we now show that infused human megakaryocytes also release platelets within the lungs of recipient mice. In addition, we observed a population of platelet-like particles (PLPs) in the infusate, which include platelets released during ex vivo growth conditions. By comparing these 2 platelet populations to human donor platelets, we found marked differences: platelets derived from infused megakaryocytes closely resembled infused donor platelets in morphology, size, and function. On the other hand, the PLP was a mixture of nonplatelet cellular fragments and nonuniform-sized, preactivated platelets mostly lacking surface CD42b that were rapidly cleared by macrophages. These data raise a cautionary note for the clinical use of human platelets released under standard ex vivo conditions. In contrast, human platelets released by intrapulmonary-entrapped megakaryocytes appear more physiologic in nature and nearly comparable to donor platelets for clinical application. PMID:25852052

  7. Incidental diagnosis of pregnancy on bone and gallium scintigraphy

    SciTech Connect

    Palestro, C.J.; Malat, J.; Collica, C.J.; Richman, A.H.

    1986-03-01

    Bone and gallium scintigraphy were performed as part of the diagnostic workup of a 21-yr-old woman who presented at our institution with a history of progressively worsening low back pain over a 1-wk period of time. The angiographic phase of the bone scan demonstrated a well-defined radionuclide blush within the pelvis just cephalad to the urinary bladder with persistent hyperemia noted in the blood-pool image. We attribute these findings to a uterine blush secondary to the pronounced uterine muscular hyperplasia, hyperemia, and edema that accompany pregnancy. Gallium scintigraphy demonstrated intense bilateral breast accumulation of the imaging agent in a typical doughnut pattern which is commonly found in the prelactating and lactating breast. Also demonstrated was apparent gallium accumulation in the placenta. This case is presented to emphasize the radionuclide findings that occur during pregnancy, particularly the incidental finding of radionuclide blush during the angiographic phase of a radionuclide scintigraphy which should alert the nuclear physician to the possibility of pregnancy in a woman of childbearing age.

  8. Thallium-201 myocardial scintigraphy in acute myocardial infarction and ischemia

    SciTech Connect

    Wackers, F.J.

    1982-04-01

    Thallium-201 scintigraphy provides a sensitive and reliable method of detecting acute myocardial infarction and ischemia when imaging is performed with understanding of the temporal characteristics and accuracy of the technique. The results of scintigraphy are related to the time interval between onset of symptoms and time of imaging. During the first 6 hr after chest pain almost all patients with acute myocardial infarction and approximately 50% of the patients with unstable angina will demonstrate /sup 201/TI pefusion defects. Delayed imaging at 2-4 hr will permit distinction between ischemia and infarction. In patients with acute myocardial infarction, the size of the perfusion defect accurately reflects the extent of the infarcted and/or jeopardized myocardium, which may be used for prognostic stratification. In view of the characteristics of /sup 201/TI scintigraphy, the most practical application of this technique is in patients in whom myocardial infarction has to be ruled out, and for early recognition of patients at high risk for complications.

  9. Role of platelet function and platelet membrane glycoproteins in children with primary immune thrombocytopenia

    PubMed Central

    Liu, Wen-Jun; Bai, Jing; Guo, Qu-Lian; Huang, Zhe; Yang, Hong; Bai, Yong-Qi

    2016-01-01

    The aim of the present study was to examine and understand changes in platelet functions prior to and after the treatment of primary immune thrombocytopenia (ITP) in children. An automatic hematology analyzer and whole blood flow cytometry were used to detect immature platelet fraction (IPF), IPC and membrane glycoproteins (CD62p, PAC-1 and CD42b) in ITP children (ITP group), children with complete response after ITP treatment (ITP-CR group) and children with elective surgery (normal control group). The results showed that, levels of platelet count (PLT) and plateletcrit in the ITP group were lower alhtough the levels of mean platelet volume, platelet distribution width and platelet-large cell ratio (P-LCR) were higher than those in the normal control and ITP-CR groups. PLT in the ITP-CR group was lower than that in the normal controls. Additionally, IPF% was higher in the normal control and ITP-CR groups, IPC was lower in the ITP group compared to the normal control and ITP-CR groups. Furthermore, prior to ADP activation, the expression levels of CD62p, PAC-1 and CD42b in the ITP group were lower in ITP group than those in the normal control and ITP-CR groups. The expression level of PAC-1 was lower in the ITP-CR and normal control groups. No differences were identified in CD62p and CD42b expression levels. Following ATP activation, CD62p, PAC-1 and CD42b expression in the ITP group was lower than that in the normal control and ITP-CR groups. PAC-1 expression was lower while CD62p expression was higher in the ITP-CR group compared to the normal control group. In conclusion, the activation of platelets in ITP children was low. Decreased platelet function, platelet parameters and platelet glycoproteins may be used as markers for monitoring the treatment efficacy in ITP children. PMID:27431926

  10. Optimized Preparation Method of Platelet-Concentrated Plasma and Noncoagulating Platelet-Derived Factor Concentrates: Maximization of Platelet Concentration and Removal of Fibrinogen

    PubMed Central

    Araki, Jun; Jona, Masahiro; Eto, Hitomi; Aoi, Noriyuki; Kato, Harunosuke; Suga, Hirotaka; Doi, Kentaro; Yatomi, Yutaka

    2012-01-01

    Abstract Platelet-rich plasma (PRP) has been clinically used as an easily prepared growth factor cocktail that can promote wound healing, angiogenesis, and tissue remodeling. However, the therapeutic effects of PRP are still controversial, due partly to the lack of optimized and standardized preparation protocols. We used whole blood (WB) samples to optimize the preparation protocols for PRP, white blood cell-containing (W-PRP), platelet-concentrated plasma (PCP), and noncoagulating platelet-derived factor concentrate (PFC). PRP and W-PRP were most efficiently collected by 10 min centrifugation in a 15-mL conical tube at 230–270 g and 70 g, respectively. To prepare PCP, platelets were precipitated by centrifugation of PRP at >2300 g, 90% of supernatant plasma was removed, and the platelets were resuspended. For preparation of noncoagulating PFC, the supernatant was replaced with one-tenth volume of saline, followed by platelet activation with thrombin. Platelet (before activation) and platelet-derived growth factor (PDGF)-BB (after activation) concentrations in PCP were approximately 20 times greater than those in WB, whereas PFC contained a 20-times greater concentration of platelets before platelet activation and a 50-times greater concentration of PDGF-BB without formation of a fibrin gel after platelet activation than WB. Surprisingly, total PDGF-BB content in the PFC was twice that of activated WB, which suggested that a substantial portion of the PDGF-BB became trapped in the fibrin glue, and replacement of plasma with saline is crucial for maximization of platelet-derived factors. As an anticoagulant, ethylene di-amine tetra-acetic acid disodium inhibited platelet aggregation more efficiently than acid citrate dextrose solution, resulting in higher nonaggregated platelet yield and final PDGF-BB content. These results increase our understanding of how to optimize and standardize preparation of platelet-derived factors at maximum concentrations. PMID

  11. Involvement of platelet cyclic GMP but not cyclic AMP suppression in leukocyte-dependent platelet adhesion to endothelial cells induced by platelet-activating factor in vitro.

    PubMed Central

    Hirafuji, M.; Nezu, A.; Shinoda, H.; Minami, M.

    1996-01-01

    1. Incubation of endothelial cells with platelets in the absence or the presence of PAF (10 nM) markedly increased platelet cyclic AMP levels, which were significantly decreased by indomethacin (3 microM). Co-incubation of endothelial cells and platelets with polymorphonuclear leukocytes (PMNs) did not change the platelet cyclic AMP levels. 2. Incubation of endothelial cells with platelets in the absence of PAF increased platelet cyclic GMP levels, which were increased 3.5 fold by PAF. These cyclic GMP levels were significantly decreased by NG-nitro-L-arginine (100 microM), and completely by methylene blue (10 microM). When endothelial cells and platelets were co-incubated with PMNs, the cyclic GMP level in the cell mixture was 42.5 and 65.3% lower than that in endothelial cells and platelets without and with PAF stimulation, respectively. 3. PAF induced platelet adhesion to endothelial cells only when PMNs were present. Methylene blue dose-dependently potentiated the PMN-dependent platelet adhesion induced by PAF, although it had no effect in the absence of PMNs. 4. Sodium nitroprusside and 8-bromo cyclic GMP but not dibutyryl cyclic AMP significantly, although partially, inhibited the platelet adhesion. Inhibition of cyclic GMP-specific phosphodiesterase by zaprinast slightly inhibited the PMN-induced platelet adhesion and potentiated the inhibitory effect of 8-bromo cyclic GMP, while these drugs markedly inhibited the adhesion of platelet aggregates induced by PMN sonicates. 5. These results suggest that the impairment by activated PMNs of EDRF-induced platelet cyclic GMP formation is involved in part in the mechanism of PMN-dependent platelet adhesion to endothelial cells induced by PAF in vitro. The precise mechanism still remains to be clarified. PMID:8789382

  12. The effect of time of day and exercise on platelet functions and platelet-neutrophil aggregates in healthy male subjects.

    PubMed

    Aldemir, Hatice; Kiliç, Nedret

    2005-12-01

    Platelet activation state changes by exercise. The effect of exercise time on platelet activation state and formation of platelet-neutrophil aggregates are not known yet. In this study the effect of exercise and time of day were examined on platelet activity with platelet-neutrophil aggregates. Ten moderately active males aged 27+/- 1.63 (mean+/-S.D.) years completed sub-maximal (70% VO(2max)) exercise trials for 30 min. Blood pressure (BP) was recorded. Venous blood samples were obtained at rest, immediately post-exercise and after 30 min of recovery. Whole blood was analysed for haematocrit (Hct), haemoglobin (Hb), platelet count (PC), mean platelet count (MPV) and platelet aggregation (PA). Platelet-neutrophil aggregates and beta-thromboglobulin (beta-TG) levels were assayed. Platelet count showed significant increase after morning exercise ((236+/- 32)x10(9) l(-1) versus (202+/- 34)x10(9) l(-1) baseline, p < 0.05). Exercise resulted in significantly lower MPV after the evening exercise (9.16+/- 0.5 fl versus 9.65+/- 0.36 fl, p < 0.05). Platelet aggregation by adenosine diphosphate (ADP) decreased after morning exercise and the recovery aggregation levels were significantly different at two different times of the day (68+/- 20% a.m. versus 80+/- 12% p.m., p < 0.05). It was also showed that platelet-neutrophil aggregates increased significantly from baseline after both exercises. Exercise-induced platelet-neutrophil aggregates were higher in the evening (10.7+/- 1.3% p.m. versus 6.4+/- 1.8% a.m., p < 0.0001). It is therefore concluded that besides platelet-platelet aggregation, exercise can cause platelet- neutrophil aggregates. In addition, time of day has an effect on platelet activation related events. Circadian variations of physiological parameters may have an effect on thrombus formation by platelet activation. PMID:16311912

  13. Hypersensitivity to thrombin of platelets from hypercholesterolemic rats

    SciTech Connect

    Winocour, P.D.; Rand, M.L.; Kinlough-Rathbone, R.L.; Mustard, J.F.

    1986-03-01

    Hypersensitivity of platelets to thrombin has been associated with hypercholesterolemia. The authors have examined the mechanisms involved in this hypersensitivity. Rats were given diets rich in milk fat and containing added cholesterol and taurocholate to produce hypercholesterolemia (HC) (262 +/- 25 mg%) or added sitosterol as a normocholesterolemic control (NC) (89 +/- 6 mg%). Washed platelets were prelabelled with /sup 14/C-serotonin. In the presence of acetylsalicyclic acid (ASA) (to inhibit thromboxane A/sub 2/ (TXA/sub 2/) formation) and creatine phosphate/creatine phosphokinase (CP/CPK) (to remove released ADP), HC platelets aggregated more (26 +/- 1%) and released more /sup 14/C (9.1 +/- 2.0%) than NC platelets (aggregation: 0%, p < 0.001; /sup 14/C release: 1.5 +/- 0.5%, p < 0.002) in response to thrombin (0.075 U/ml). Thus, a pathway independent of released ADP or TXA/sub 2/ formation is involved in the hypersensitivity of HC platelets to thrombin. Total binding of /sup 125/I-thrombin to HC platelets was less than that to NC platelets but HC platelets were smaller and had less protein than NC platelets; the thrombin binding per mg platelet protein was the same for HC and NC platelets, indicating that hypersensitivity to thrombin of HC platelets does not result from increased thrombin binding. Thus, hypersensitivity of HC platelets to thrombin is not due to TXA/sub 2/ formation, the action of released ADP or increased thrombin binding.

  14. Equid herpesvirus type 1 activates platelets.

    PubMed

    Stokol, Tracy; Yeo, Wee Ming; Burnett, Deborah; DeAngelis, Nicole; Huang, Teng; Osterrieder, Nikolaus; Catalfamo, James

    2015-01-01

    Equid herpesvirus type 1 (EHV-1) causes outbreaks of abortion and neurological disease in horses. One of the main causes of these clinical syndromes is thrombosis in placental and spinal cord vessels, however the mechanism for thrombus formation is unknown. Platelets form part of the thrombus and amplify and propagate thrombin generation. Here, we tested the hypothesis that EHV-1 activates platelets. We found that two EHV-1 strains, RacL11 and Ab4 at 0.5 or higher plaque forming unit/cell, activate platelets within 10 minutes, causing α-granule secretion (surface P-selectin expression) and platelet microvesiculation (increased small events double positive for CD41 and Annexin V). Microvesiculation was more pronounced with the RacL11 strain. Virus-induced P-selectin expression required plasma and 1.0 mM exogenous calcium. P-selectin expression was abolished and microvesiculation was significantly reduced in factor VII- or X-deficient human plasma. Both P-selectin expression and microvesiculation were re-established in factor VII-deficient human plasma with added purified human factor VIIa (1 nM). A glycoprotein C-deficient mutant of the Ab4 strain activated platelets as effectively as non-mutated Ab4. P-selectin expression was abolished and microvesiculation was significantly reduced by preincubation of virus with a goat polyclonal anti-rabbit tissue factor antibody. Infectious virus could be retrieved from washed EHV-1-exposed platelets, suggesting a direct platelet-virus interaction. Our results indicate that EHV-1 activates equine platelets and that α-granule secretion is a consequence of virus-associated tissue factor triggering factor X activation and thrombin generation. Microvesiculation was only partly tissue factor and thrombin-dependent, suggesting the virus causes microvesiculation through other mechanisms, potentially through direct binding. These findings suggest that EHV-1-induced platelet activation could contribute to the thrombosis that occurs in

  15. Akt signaling in platelets and thrombosis

    PubMed Central

    Woulfe, Donna S

    2010-01-01

    Akt is a Ser–Thr kinase with pleiotropic effects on cell survival, growth and metabolism. Recent evidence from gene-deletion studies in mice, and analysis of human platelets treated with Akt inhibitors, suggest that Akt regulates platelet activation, with potential consequences for thrombosis. Akt activation is regulated by the level of phosphoinositide 3-phosphates, and proteins that regulate concentrations of this lipid also regulate Akt activation and platelet function. Although the effectors through which Akt contributes to platelet activation are not definitively known, several candidates are discussed, including endothelial nitric oxide synthase, glycogen synthase kinase 3β, phosphodiesterase 3A and the integrin β3 tail. Selective inhibitors of Akt isoforms or of proteins that contribute to its activation, such as individual PI3K isoforms, may make attractive targets for antithrombotic therapy. This review summarizes the current literature describing Akt activity and its regulation in platelets, including speculation regarding the future of Akt or its regulatory pathways as targets for the development of antithrombotic therapies. PMID:20352060

  16. Migraine patients show increased platelet vasopressin receptors.

    PubMed

    Buschmann, J; Leppla-Wollsiffer, G; Nemeth, N; Nelson, K; Kirsten, R

    1996-01-01

    This study was designed to investigate vasopressin receptor status (Bmax and Kd) on platelets, vasopressin plasma levels, and vasopressin-induced platelet aggregation in migraine patients (21 females and 6 males) during a headache-free interval and in a matched control group. In the migraine group, Bmax was significantly higher (P = 0.02) at 53.9 +/- 20.6 fmol/mg than in the control group (36.8 +/- 21.0 fmol/mg). A correlation between Bmax and high or low sensitivity to vasopressin as an aggregator was evident in the control group, but not in the migraine group. No differences in Kd or in plasma levels of vasopressin between the migraine and control group were apparent. Men in both groups were much less sensitive to vasopressin as a platelet aggregator than were women (P < 0.01). Whether the higher Bmax in the migraine group is a reflection of temporarily higher vasopressin levels during headache or reflects a primary increase in sensitivity to vasopressin, remains to be clarified. The higher sensitivity of platelets (as a model for vessel wall receptors) from women may indicate why many more women than men suffer from migraine. Since the Bmax of the vasopressin receptor on platelets from migraine patients is increased compared to controls, treating migraine headache with vasopressin may deserve more attention. PMID:8990597

  17. Platelets in aspirin-exacerbated respiratory disease

    PubMed Central

    Laidlaw, Tanya M.; Boyce, Joshua A.

    2015-01-01

    Aspirin-exacerbated respiratory disease (AERD) is a chronic inflammatory disease characterized clinically by the triad of asthma, nasal polyposis, and pathognomonic respiratory reactions after ingestion of aspirin. It is a distinct syndrome associated with eosinophilic infiltration of respiratory tissues and excessive production of cysteinyl leukotrienes. Despite the consistent clinical phenotype of the respiratory disease, the underlying pathogenesis of the disease remains unclear. In addition to their role in hemostasis, platelets have the capacity to influence the activation state and function of other immune cells during inflammation, and to facilitate granulocyte recruitment into the tissues. Platelets also possess a repertoire of potent pre-formed mediators of inflammation that are released upon activation, and are a rich source of newly-synthesized lipid mediators that alter vascular permeability and smooth muscle tone. Accordingly, the activity of platelets has been linked to diverse inflammatory diseases, including asthma. Both human and animal studies strongly suggest that platelet activity is uniquely associated with the pathophysiology of AERD. This article summarizes the evidence supporting an effector role for platelets in asthma in general and in AERD in particular, and considers the potential therapeutic implications. PMID:26051947

  18. A manual method to obtain platelet rich plasma

    PubMed Central

    Marques, Fabiana Paulino; Ingham, Sheila Jean McNeill; Forgas, Andrea; Franciozi, Carlos Eduardo da Silveira; Sasaki, Pedro Henrique; Abdalla, Rene Jorge

    2014-01-01

    OBJECTIVE: This study is to report a manual method to obtain platelet rich plasma (PRP). METHODS: For this study 61 ml of peripheral blood was obtained and submitted to centrifugation at 541g for 5 min. The centrifugation separates the blood into three components: red blood cells, buffy coat and platelet rich plasma. Blood and platelet rich plasma samples were sent to the Hospital's Laboratory and platelets and leukocytes were measured. RESULTS: A sample of 637 blood donors was evaluated. The platelet yield efficiency was 86.77% and the increase in platelet concentration factor was 2.89 times. The increase in leukocyte concentration factor was 1.97 times. CONCLUSION: The method described here produces leukocyte-rich and platelet-rich plasma with a high platelet and leukocyte increased factor. Level of Evidence IV, Controlled Laboratory Study. PMID:24868183

  19. Platelet activation during angiotensin II infusion in healthy volunteers.

    PubMed

    Larsson, P T; Schwieler, J H; Wallén, N H

    2000-01-01

    The present study was undertaken to evaluate the effects of an intravenous infusion of angiotensin II (10 ng/kg per min) on platelet function and coagulation in vivo in 18 healthy males. The infusion increased mean arterial pressure by 23+/-2 mm Hg. Plasma beta-thromboglobulin levels, reflecting platelet secretion, increased by 66+/-24% during the infusion, as did also platelet surface expression of P-selectin as measured by flow cytometry. Platelet fibrinogen binding increased, whereas platelet aggregability, assessed by ex vivo filtragometry, was unaltered. Angiotensin II caused mild activation of the coagulation cascade with increases in plasma levels of thrombin-antithrombin complex and prothrombin fragment F1 + 2. In conclusion, angiotensin II has mild platelet-activating effects in vivo and also enhances coagulation. Markers of platelet secretion are significantly increased, whereas markers of platelet aggregability are less affected. The clinical relevance of these findings remains to be clarified. PMID:10691100

  20. Engineering Factor Xa Inhibitor with Multiple Platelet-Binding Sites Facilitates its Platelet Targeting

    PubMed Central

    Zhu, Yuanjun; Li, Ruyi; Lin, Yuan; Shui, Mengyang; Liu, Xiaoyan; Chen, Huan; Wang, Yinye

    2016-01-01

    Targeted delivery of antithrombotic drugs centralizes the effects in the thrombosis site and reduces the hemorrhage side effects in uninjured vessels. We have recently reported that the platelet-targeting factor Xa (FXa) inhibitors, constructed by engineering one Arg-Gly-Asp (RGD) motif into Ancylostoma caninum anticoagulant peptide 5 (AcAP5), can reduce the risk of systemic bleeding than non-targeted AcAP5 in mouse arterial injury model. Increasing the number of platelet-binding sites of FXa inhibitors may facilitate their adhesion to activated platelets, and further lower the bleeding risks. For this purpose, we introduced three RGD motifs into AcAP5 to generate a variant NR4 containing three platelet-binding sites. NR4 reserved its inherent anti-FXa activity. Protein-protein docking showed that all three RGD motifs were capable of binding to platelet receptor αIIbβ3. Molecular dynamics simulation demonstrated that NR4 has more opportunities to interact with αIIbβ3 than single-RGD-containing NR3. Flow cytometry analysis and rat arterial thrombosis model further confirmed that NR4 possesses enhanced platelet targeting activity. Moreover, NR4-treated mice showed a trend toward less tail bleeding time than NR3-treated mice in carotid artery endothelium injury model. Therefore, our data suggest that engineering multiple binding sites in one recombinant protein is a useful tool to improve its platelet-targeting efficiency. PMID:27432161

  1. Xanthohumol, a Prenylated Flavonoid from Hops (Humulus lupulus), Prevents Platelet Activation in Human Platelets

    PubMed Central

    Lee, Ye-Ming; Hsieh, Kuo-Hsien; Lu, Wan-Jung; Chou, Hsiu-Chu; Chou, Duen-Suey; Lien, Li-Ming; Sheu, Joen-Rong; Lin, Kuan-Hung

    2012-01-01

    Xanthohumol is the principal prenylated flavonoid in the hop plant (Humulus lupulus L.). Xanthohumol was found to be a very potent cancer chemopreventive agent through regulation of diverse mechanisms. However, no data are available concerning the effects of xanthohumol on platelet activation. The aim of this paper was to examine the antiplatelet effect of xanthohumol in washed human platelets. In the present paper, xanthohumol exhibited more-potent activity in inhibiting platelet aggregation stimulated by collagen. Xanthohumol inhibited platelet activation accompanied by relative [Ca2+]i mobilization, thromboxane A2 formation, hydroxyl radical (OH●) formation, and phospholipase C (PLC)γ2, protein kinase C (PKC), mitogen-activated protein kinase (MAPK), and Akt phosphorylation. Neither SQ22536, an inhibitor of adenylate cyclase, nor ODQ, an inhibitor of guanylate cyclase, reversed the xanthohumol-mediated inhibitory effect on platelet aggregation. Furthermore, xanthohumol did not significantly increase nitrate formation in platelets. This study demonstrates for the first time that xanthohumol possesses potent antiplatelet activity which may initially inhibit the PI3-kinase/Akt, p38 MAPK, and PLCγ2-PKC cascades, followed by inhibition of the thromboxane A2 formation, thereby leading to inhibition of [Ca2+]i and finally inhibition of platelet aggregation. Therefore, this novel role of xanthohumol may represent a high therapeutic potential for treatment or prevention of cardiovascular diseases. PMID:22611436

  2. Engineering Factor Xa Inhibitor with Multiple Platelet-Binding Sites Facilitates its Platelet Targeting.

    PubMed

    Zhu, Yuanjun; Li, Ruyi; Lin, Yuan; Shui, Mengyang; Liu, Xiaoyan; Chen, Huan; Wang, Yinye

    2016-01-01

    Targeted delivery of antithrombotic drugs centralizes the effects in the thrombosis site and reduces the hemorrhage side effects in uninjured vessels. We have recently reported that the platelet-targeting factor Xa (FXa) inhibitors, constructed by engineering one Arg-Gly-Asp (RGD) motif into Ancylostoma caninum anticoagulant peptide 5 (AcAP5), can reduce the risk of systemic bleeding than non-targeted AcAP5 in mouse arterial injury model. Increasing the number of platelet-binding sites of FXa inhibitors may facilitate their adhesion to activated platelets, and further lower the bleeding risks. For this purpose, we introduced three RGD motifs into AcAP5 to generate a variant NR4 containing three platelet-binding sites. NR4 reserved its inherent anti-FXa activity. Protein-protein docking showed that all three RGD motifs were capable of binding to platelet receptor αIIbβ3. Molecular dynamics simulation demonstrated that NR4 has more opportunities to interact with αIIbβ3 than single-RGD-containing NR3. Flow cytometry analysis and rat arterial thrombosis model further confirmed that NR4 possesses enhanced platelet targeting activity. Moreover, NR4-treated mice showed a trend toward less tail bleeding time than NR3-treated mice in carotid artery endothelium injury model. Therefore, our data suggest that engineering multiple binding sites in one recombinant protein is a useful tool to improve its platelet-targeting efficiency. PMID:27432161

  3. Predictors of Symptom Development in Intermediate Carotid Artery Stenosis: Mean Platelet Volume and Platelet Distribution Width.

    PubMed

    Koklu, Erkan; Yuksel, Isa Oner; Arslan, Sakir; Cagirci, Goksel; Gencer, Elif Sarionder; Koc, Pinar; Cay, Serkan; Kizilirmak, Filiz; Esin, Murat

    2016-08-01

    Platelets play an important role in the pathogenesis of atherothrombosis. Platelet activation is associated with increased mean platelet volume (MPV) and platelet distribution width (PDW). In this study, we investigated the relation of MPV and PDW with the risk of stroke in patients with intermediate (50%-70%) carotid artery stenosis. A total of 254 patients (115 symptomatic and 139 asymptomatic) with intermediate carotid artery stenosis were enrolled in this study. Symptomatic and asymptomatic patients were compared in regard to MPV and PDW. Mean platelet volume was significantly greater in the symptomatic group compared with the asymptomatic group (11.1 and 9.4 fL, respectively; P < .001). Platelet distribution width was significantly greater in the symptomatic group compared with the asymptomatic group (15.0% and 11.9%, respectively; P < .001). Multivariate regression analysis showed that an MPV ≥10.2 fL and a PDW ≥14.3% were independent predictors of developing symptomatic carotid artery stenosis. Mean platelet volume and PDW are increased in the presence of symptomatic intermediate carotid artery stenosis. Increased MPV and PDW may be independent predictors of developing symptomatic carotid artery plaque. PMID:26514416

  4. The content of bone morphogenetic proteins in platelets varies greatly between different platelet donors

    SciTech Connect

    Kalen, Anders; Wahlstroem, Ola; Linder, Cecilia Halling; Magnusson, Per

    2008-10-17

    Platelet derivates and platelet rich plasma have been used to stimulate bone formation and wound healing because of the rich content of potent growth factors. However, not all reports have been conclusive since some have not been able to demonstrate a positive effect. We investigated the interindividual variation of bone morphogenetic proteins (BMPs) in platelets from healthy donors, and the pH-dependent effect on the release of BMPs in preparations of lysed platelets in buffer (LPB). Platelet concentrates from 31 healthy donors were prepared in pH 4.3 and pH 7.4 buffers and investigated with respect to BMP-2, -4, -6, and -7. BMP-2 and BMP-4 were significantly more common in acidic LPBs in comparison with neutral preparations. We also observed a considerable variation among platelet donors with respect to the release of BMPs at pH 4.3 and 7.4. In conclusion, a considerable variation was found among platelet donors, which may be of importance considering the ambiguous results previously reported on osteoblast proliferation and differentiation.

  5. Gallbladder Activity on 99mTc-Labeled Red Cell Scintigraphy Confirmed by SPECT/CT Imaging.

    PubMed

    Wang, Ling; Jing, Hongli; Chen, Libo; Wang, Zhenghua; Li, Fang

    2016-09-01

    Tc-labeled red cell (Tc-RBC) scintigraphy is commonly used to detect gastrointestinal bleeding. Gallbladder visualization on Tc-RBC scintigraphy is not common. We present a case of gallbladder visualization on Tc-RBC scintigraphy confirmed by SPECT/CT imaging in a patient with chronic renal failure and anemia. PMID:27405034

  6. A more practical therapy for low platelets.

    PubMed

    Torres, G

    1996-01-01

    The Food and Drug Administration (FDA) approved WinRho as a new treatment for ITP or thrombocytopenic purpura (low blood platelet count) in people with HIV. Current treatment options for ITP include AZT, corticosteroids, immunoglobulin therapy, and splenectomy. Clinical evaluation rates AZT as the best of the options. WinRho treatment will not work on Rh-negative patients or patients with no spleen. The largest WinRho study to date, involving 267 patients, shows a mean platelet increase of 76,000 cells with no adverse effect on CD4 counts or evidence of an acceleration of HIV disease progression. HIV-positive patients had a poorer platelet increase response than HIV-negative patients. PMID:11363379

  7. Characteristics of rat platelets and relative contributions of platelets and blood coagulation to haemostasis.

    PubMed

    Takahashi, O

    2000-01-01

    In order to understand some of the haemostatic mechanisms in rats for the interpretation of toxicological data, basic haemostatic parameters with a special emphasis on platelet functions were first measured in vitro. The results of reactions of rat platelets to many aggregating agents suggest that only ADP may be a consistently significant aggregator. The search for physiologic aggregators revealed ADP to be available from erythrocytes. Adhesion reaction also required ADP. Collagen was not considered to be essential for either reaction. Aggregation and adhesion were probably both reversible in flowing blood, while irreversible thrombi were formed in blood at rest ex vivo. Blood coagulation parameters determined revealed that the intrinsic pathway may be more important than the extrinsic one. The rate of intrinsic coagulation reaction was rapid, and plasma coagulation appeared to be of primary importance while the influence of platelet aggregation was minor. A simple model of rat haemostatic mechanism is proposed based on these results. Additionally, to define the relative contribution of platelets versus other cellular and plasma coagulation in vivo, rats were administered antiplatelet drugs (ticlopidine, suprofen and clopidogrel) and an anticoagulant (warfarin) intraperitoneally. Bleeding times (BTs) were significantly increased in all treated groups. ADP-induced platelet aggregations were significantly depressed by the administration of the three antiplatelet drugs, while kaolon-activated partial thromboplastin time and prothrombin time were greatly increased in the warfarin-treated rats. The increase in BT may be due to the inhibition of platelet activity or blood coagulation defect in rats given antiplatelet drugs or warfarin, respectively. These results suggest that platelets play a key role in haemostasis in the rat. Two possible explanations of the disparity between in vitro and in vivo results may be that functional tests used here are not adequate to cover

  8. Assessing the Methodology for Calculating Platelet Contribution to Clot Strength (Platelet Component) in Thromboelastometry and Thrombelastography

    PubMed Central

    Ranucci, Marco; Hochleitner, Gerald; Schöchl, Herbert; Schlimp, Christoph J.

    2015-01-01

    The viscoelastic properties of blood clot have been studied most commonly using thrombelastography (TEG®) and thromboelastometry (ROTEM®). ROTEM®-based bleeding treatment algorithms recommend administering platelets to patients with low EXTEM clot strength (e.g., clot amplitude at 10 minutes [A10] <40 mm) once clot strength of the ROTEM® fibrin-based test (FIBTEM) is corrected. Algorithms based on TEG® typically use a low value of maximum amplitude (e.g., <50 mm) as a trigger for administering platelets. However, this parameter reflects the contributions of various blood components to the clot, including platelets and fibrin/fibrinogen. The platelet component of clot strength may provide a more sensitive indication of platelet deficiency than clot amplitude from a whole blood TEG® or ROTEM® assay. The platelet component of the formed clot is derived from the results of TEG®/ROTEM® tests performed with and without platelet inhibition. In this article, we review the basis for why this calculation should be based on clot elasticity (e.g., the E parameter with TEG® and the CE parameter with ROTEM®) as opposed to clot amplitude (e.g., the A parameter with TEG® or ROTEM®). This is because clot elasticity, unlike clot amplitude, reflects the force with which the blood clot resists rotation within the device, and the relationship between clot amplitude (variable X) and clot elasticity (variable Y) is nonlinear. A specific increment of X (ΔX) will be associated with different increments of Y (ΔY), depending on the initial value of X. When calculated correctly, using clot elasticity data, the platelet component of the clot can provide a valuable insight into platelet deficiency in emergency bleeding. PMID:26378699

  9. Platelet concentration in platelet concentrates and periodontal regeneration-unscrambling the ambiguity

    PubMed Central

    Suchetha, A.; Lakshmi, P.; Bhat, Divya; Mundinamane, Darshan B.; Soorya, K. V.; Bharwani, G. Ashit

    2015-01-01

    Context: Platelet-rich-plasma (PRP) and Platelet-rich-fibrin (PRF) are extensively used autologous platelet concentrates in periodontal regeneration, and PRF has a better efficacy as compared to PRP. The rationale for this difference has often been attributed to the difference in the structure of the fibrin matrix. However, the effect of concentration of platelets on the regenerative potential of these concentrates is obscure. Aims: The study was conducted to evaluate and compare, clinically and radiographically, the efficacy of PRF and PRP in the treatment of periodontal endosseous defects and to assess the effect of platelet concentration on periodontal regeneration. Materials and Methods: Twenty intrabony defects were selected and divided into two groups randomly by the coin toss method. Group I received PRP and Group II subjects were treated with PRF. The platelet counts in PRP and PRF were analyzed. Clinical and radiological parameters were assessed at baseline and 3, 6, and 9 months postoperatively. Statistical Analysis: Kruskal–Wallis Chi-square test, Wilcoxon signed rank test, t-test, and Spearman's rank correlation were used for statistical analysis of data. Results: There was statistically significant improvement in all the parameters in the two groups except in relation to gingival recession. There was a statistically significant difference between the platelet count in Group I and Group II (P = 0.002). Conclusion: PRP and PRF appear to have nearly comparable effects in terms of periodontal regeneration. The concentration of platelets appears to play a paradoxical role in regeneration. The regenerative potential of platelets appears to be optimal within a limited range. PMID:26681857

  10. Platelets and their interactions with other immune cells

    PubMed Central

    Lam, Fong W.; Vijayan, K. Vinod; Rumbaut, Rolando E.

    2015-01-01

    Platelets are anucleate blood cells, long known to be critically involved in hemostasis and thrombosis. In addition to their role in blood clots, increasing evidence reveals significant roles for platelets in inflammation and immunity. However, the notion that platelets represent immune cells is not broadly recognized in the field of Physiology. This manuscript reviews the role of platelets in inflammation and immune responses, and highlights their interactions with other immune cells, including examples of major functional consequences of these interactions. PMID:26140718

  11. Receptors and signalling mechanisms in the procoagulant response of platelets.

    PubMed

    Heemskerk, J W; Siljander, P R; Bevers, E M; Farndale, R W; Lindhout, T

    2000-09-01

    Platelets in an advanced stage of activation change from coagulation-inactive to coagulation-promoting cells. This procoagulant response is characterised by exposure of aminophospholipids, such as phosphatidylserine, to the platelet surface and by formation of microvesicles. Under specific conditions, when both signalling and adhesive platelet receptors are occupied, collagen and also thrombin are able to trigger this response. Thus, platelets express high coagulation-promoting activity only after interacting with multiple receptors. PMID:11083453

  12. Failure of Gallium-67 scintigraphy to identify reliably noninfectious interstitial nephritis: concise communication

    SciTech Connect

    Graham, G.D.; Lundy, M.M.; Moreno, A.J.

    1983-07-01

    Gallium-67 scintigraphy has been reported to be useful in the diagnosis of noninfectious interstitial nephritis. We studied 12 patients with Ga-67 citrate that were diagnosed as having noninfectious interstitial nephritis on renal biopsy. Only seven of the twelve patients with interstitial nephritis on biopsy were scan-positive. Gallium-67 scintigraphy may not reliably identify noninfectious interstitial nephritis.

  13. Pegylation increases platelet biocompatibility of gold nanoparticles.

    PubMed

    Santos-Martinez, Maria Jose; Rahme, Kamil; Corbalan, J Jose; Faulkner, Colm; Holmes, Justin D; Tajber, Lidia; Medina, Carlos; Radomski, Marek Witold

    2014-06-01

    The increasing use of gold nanoparticles in medical diagnosis and treatment has raised the concern over their blood compatibility. The interactions of nanoparticles with blood components may lead to platelet aggregation and endothelial dysfunction. Therefore, medical applications of gold nanoparticles call for increased nanoparticle stability and biocompatibility. Functionalisation of nanoparticles with polythelene glycol (PEGylation) is known to modulate cell-particle interactions. Therefore, the aim of the current study was to investigate the effects of PEGylated-gold nanoparticles on human platelet function and endothelial cells in vitro. Gold nanoparticles, 15 nm in diameter, were synthesised in water using sodium citrate as a reducing and stabilising agent. Functionalised polyethylene glycol-based thiol polymers were used to coat and stabilise pre-synthesised gold nanoparticles. The interaction of gold nanoparticles-citrate and PEGylated-gold nanoparticles with human platelets was measured by Quartz Crystal Microbalance with Dissipation. Platelet-nanoparticles interaction was imaged using phase-contrast, scanning and transmission electron microscopy. The inflammatory effects of gold nanoparticles-citrate and PEGylated-gold nanoparticles in endothelial cells were measured by quantitative real time polymerase chain reaction. PEGylated-gold nanoparticles were stable under physiological conditions and PEGylated-gold nanoparticles-5400 and PEGylated-gold nanoparticles-10800 did not affect platelet aggregation as measured by Quartz Crystal Microbalance with Dissipation. In addition, PEGylated-gold nanoparticles did not induce an inflammatory response when incubated with endothelial cells. Therefore, this study shows that PEGylated-gold nanoparticles with a higher molecular weight of the polymer chain are both platelet- and endothelium-compatible making them attractive candidates for biomedical applications. PMID:24749395

  14. Rupture Forces among Human Blood Platelets at different Degrees of Activation.

    PubMed

    Nguyen, Thi-Huong; Palankar, Raghavendra; Bui, Van-Chien; Medvedev, Nikolay; Greinacher, Andreas; Delcea, Mihaela

    2016-01-01

    Little is known about mechanics underlying the interaction among platelets during activation and aggregation. Although the strength of a blood thrombus has likely major biological importance, no previous study has measured directly the adhesion forces of single platelet-platelet interaction at different activation states. Here, we filled this void first, by minimizing surface mediated platelet-activation and second, by generating a strong adhesion force between a single platelet and an AFM cantilever, preventing early platelet detachment. We applied our setup to measure rupture forces between two platelets using different platelet activation states, and blockade of platelet receptors. The rupture force was found to increase proportionally to the degree of platelet activation, but reduced with blockade of specific platelet receptors. Quantification of single platelet-platelet interaction provides major perspectives for testing and improving biocompatibility of new materials; quantifying the effect of drugs on platelet function; and assessing the mechanical characteristics of acquired/inherited platelet defects. PMID:27146004

  15. Rupture Forces among Human Blood Platelets at different Degrees of Activation

    PubMed Central

    Nguyen, Thi-Huong; Palankar, Raghavendra; Bui, Van-Chien; Medvedev, Nikolay; Greinacher, Andreas; Delcea, Mihaela

    2016-01-01

    Little is known about mechanics underlying the interaction among platelets during activation and aggregation. Although the strength of a blood thrombus has likely major biological importance, no previous study has measured directly the adhesion forces of single platelet-platelet interaction at different activation states. Here, we filled this void first, by minimizing surface mediated platelet-activation and second, by generating a strong adhesion force between a single platelet and an AFM cantilever, preventing early platelet detachment. We applied our setup to measure rupture forces between two platelets using different platelet activation states, and blockade of platelet receptors. The rupture force was found to increase proportionally to the degree of platelet activation, but reduced with blockade of specific platelet receptors. Quantification of single platelet-platelet interaction provides major perspectives for testing and improving biocompatibility of new materials; quantifying the effect of drugs on platelet function; and assessing the mechanical characteristics of acquired/inherited platelet defects. PMID:27146004

  16. Ultraviolet irradiation of platelet concentrate abrogates lymphocyte activation without affecting platelet function in vitro

    SciTech Connect

    Kahn, R.A.; Duffy, B.F.; Rodey, G.G.

    1985-11-01

    We studied the effect of ultraviolet (UV) radiation on platelet concentrates. Samples irradiated at 310 mm for 30 minutes at a dose of 1782 J per m2 showed no loss of platelet function in vitro as determined by adenosine diphosphate, collagen, or ristocetin-induced aggregation. Lymphocytes isolated from irradiated units were unable to act as responders or stimulators in a mixed-lymphocyte reaction. These data suggest that UV radiation of platelet concentrates may result in a cell suspension that is unable to evoke an immunological response.

  17. Effects of Isotretinoin on the Platelet Counts and the Mean Platelet Volume in Patients with Acne Vulgaris

    PubMed Central

    Ugur Bilgin, Aynur

    2014-01-01

    Aim. The aim of this study was to evaluate the platelet counts and the mean platelet volume in patients who received isotretinoin for the treatment of acne vulgaris. Method. A total of 110 patients were included in this retrospective study. Complete blood count parameters were recorded prior to and three-months following the treatment. Results. Both platelet counts and the mean platelet volume were significantly decreased following the treatment. No significant differences were noted on the levels of hemoglobin, hematocrit, and white blood cell count. Conclusion. Platelet counts and mean platelet volume significantly decreased following isotretinoin treatment. Since the decrease of platelet counts and the mean platelet volume was seen concomitantly, it is concluded that the effect of isotretinoin was through the suppression of bone marrow. PMID:24605049

  18. Necrotic platelets provide a procoagulant surface during thrombosis.

    PubMed

    Hua, Vu Minh; Abeynaike, Latasha; Glaros, Elias; Campbell, Heather; Pasalic, Leonardo; Hogg, Philip J; Chen, Vivien M Y

    2015-12-24

    A subpopulation of platelets fulfills a procoagulant role in hemostasis and thrombosis by enabling the thrombin burst required for fibrin formation and clot stability at the site of vascular injury. Excess procoagulant activity is linked with pathological thrombosis. The identity of the procoagulant platelet has been elusive. The cell death marker 4-[N-(S-glutathionylacetyl)amino]phenylarsonous acid (GSAO) rapidly enters a subpopulation of agonist-stimulated platelets via an organic anion-transporting polypeptide and is retained in the cytosol through covalent reaction with protein dithiols. Labeling with GSAO, together with exposure of P-selectin, distinguishes necrotic from apoptotic platelets and correlates with procoagulant potential. GSAO(+) platelets form in occluding murine thrombi after ferric chloride injury and are attenuated with megakaryocyte-directed deletion of the cyclophilin D gene. These platelets form a procoagulant surface, supporting fibrin formation, and reduction in GSAO(+) platelets is associated with reduction in platelet thrombus size and fibrin formation. Analysis of platelets from human subjects receiving aspirin therapy indicates that these procoagulant platelets form despite aspirin therapy, but are attenuated by inhibition of the necrosis pathway. These findings indicate that the major subpopulation of platelets involved in fibrin formation are formed via regulated necrosis involving cyclophilin D, and that they may be targeted independent of platelet activation. PMID:26474813

  19. Platelet glycoprotein Ibα supports experimental lung metastasis

    PubMed Central

    Jain, Shashank; Zuka, Masahiko; Liu, Jungling; Russell, Susan; Dent, Judith; Guerrero, José A.; Forsyth, Jane; Maruszak, Brigid; Gartner, T. Kent; Felding-Habermann, Brunhilde; Ware, Jerry

    2007-01-01

    The platelet paradigm in hemostasis and thrombosis involves an initiation step that depends on platelet membrane receptors binding to ligands on a damaged or inflamed vascular surface. Once bound to the surface, platelets provide a unique microenvironment supporting the accumulation of more platelets and the elaboration of a fibrin-rich network produced by coagulation factors. The platelet-specific receptor glycoprotein (GP) Ib-IX, is critical in this process and initiates the formation of a platelet-rich thrombus by tethering the platelet to a thrombogenic surface. A role for platelets beyond the hemostasis/thrombosis paradigm is emerging with significant platelet contributions in both tumorigenesis and inflammation. We have established congenic (N10) mouse colonies (C57BL/6J) with dysfunctional GP Ib-IX receptors in our laboratory that allow us an opportunity to examine the relevance of platelet GP Ib-IX in syngeneic mouse models of experimental metastasis. Our results demonstrate platelet GP Ib-IX contributes to experimental metastasis because a functional absence of GP Ib-IX correlates with a 15-fold reduction in the number of lung metastatic foci using B16F10.1 melanoma cells. The results demonstrate that the extracellular domain of the α-subunit of GP Ib is the structurally relevant component of the GP Ib-IX complex contributing to metastasis. Our results support the hypothesis that platelet GP Ib-IX functions that support normal hemostasis or pathologic thrombosis also contribute to tumor malignancy. PMID:17494758

  20. RhoGAPs and Rho GTPases in platelets.

    PubMed

    Elvers, Margitta

    2016-08-01

    Platelet cytoskeletal reorganization is essential for platelet adhesion and thrombus formation in hemostasis and thrombosis. The Rho GTPases RhoA, Rac1 and Cdc42 are the main players in cytoskeletal dynamics of platelets responsible for the formation of filopodia and lamellipodia to strongly increase the platelet surface upon activation. They are involved in platelet activation and aggregate formation including platelet secretion, integrin activation and arterial thrombus formation. The activity of Rho GTPases is tightly controlled by different proteins such as GTPase-activating proteins (GAPs). GAPs stimulate GTP hydrolysis to terminate Rho signaling. The role and impact of GAPs in platelets is not well-defined and many of the RhoGAPs identified are not known to be present in platelets or to have any function in platelets. The recently identified RhoGAPs Oligophrenin1 (OPHN1) and Nadrin regulate the activity of RhoA, Rac1 and Cdc42 and subsequent platelet cytoskeletal reorganization, platelet activation and thrombus formation. In the last years, the analysis of genetically modified mice helped to gain the understanding of Rho GTPases and their regulators in cytoskeletal rearrangements and other Rho mediated cellular processes in platelets. PMID:25639730

  1. Bidirectional effects of dexmedetomidine on human platelet functions in vitro.

    PubMed

    Kawamoto, Shuji; Hirakata, Hideo; Sugita, Naoko; Fukuda, Kazuhiko

    2015-11-01

    Platelets express the imidazoline (I)-receptor, I1 and I2, as well as the α2-adrenoceptor. Although dexmedetomidine, a selective α2-adrenoceptor agonist with some affinity for the I-receptor is expected to affect platelet function, the effects of dexmedetomidine on platelet functions remain unclear. In the present study, we investigated the effects of dexmedetomidine on human platelet functions in vitro. The effects of dexmedetomidine on platelet aggregation were examined using aggregometers. The formation of cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP) in platelets was measured by an enzyme immunoassay. In addition, P-selectin expression in platelets was estimated by flow cytometry. We showed that dexmedetomidine enhances platelet aggregation. But in the presence of yohimbine, an α2-antagonist, dexmedetomidine suppressed platelet aggregation. Efaroxan, an I1-antagonist, and methylene blue, a soluble guanylate cyclase inhibitor, abolished the suppressive effect of dexmedetomidine, whereas idazoxan, an I2-antagonist, showed no effect. Dexmedetomidine suppressed cAMP formation and enhanced P-selectin expression in platelets, and these effects were inhibited by yohimbine. Dexmedetomidine increased cGMP formation in platelets in the presence of yohimbine, and this increase was suppressed by efaroxan. These results demonstrated that dexmedetomidine has both enhancing and suppressive effects on human platelet functions through its action on the α2-adrenoceptor and on the I1-imidazoline receptor, respectively. PMID:26435028

  2. Necrotic platelets provide a procoagulant surface during thrombosis

    PubMed Central

    Hua, Vu Minh; Abeynaike, Latasha; Glaros, Elias; Campbell, Heather; Pasalic, Leonardo; Chen, Vivien M. Y.

    2015-01-01

    A subpopulation of platelets fulfills a procoagulant role in hemostasis and thrombosis by enabling the thrombin burst required for fibrin formation and clot stability at the site of vascular injury. Excess procoagulant activity is linked with pathological thrombosis. The identity of the procoagulant platelet has been elusive. The cell death marker 4-[N-(S-glutathionylacetyl)amino]phenylarsonous acid (GSAO) rapidly enters a subpopulation of agonist-stimulated platelets via an organic anion-transporting polypeptide and is retained in the cytosol through covalent reaction with protein dithiols. Labeling with GSAO, together with exposure of P-selectin, distinguishes necrotic from apoptotic platelets and correlates with procoagulant potential. GSAO+ platelets form in occluding murine thrombi after ferric chloride injury and are attenuated with megakaryocyte-directed deletion of the cyclophilin D gene. These platelets form a procoagulant surface, supporting fibrin formation, and reduction in GSAO+ platelets is associated with reduction in platelet thrombus size and fibrin formation. Analysis of platelets from human subjects receiving aspirin therapy indicates that these procoagulant platelets form despite aspirin therapy, but are attenuated by inhibition of the necrosis pathway. These findings indicate that the major subpopulation of platelets involved in fibrin formation are formed via regulated necrosis involving cyclophilin D, and that they may be targeted independent of platelet activation. PMID:26474813

  3. Binding of heparin to human platelet factor 4.

    PubMed Central

    Cowan, S W; Bakshi, E N; Machin, K J; Isaacs, N W

    1986-01-01

    Platelet factor 4 is a small protein (Mr 7756) from the alpha-granules of blood platelets which binds strongly to and neutralizes the anticoagulant properties of heparin. From an analysis of X-ray crystallographic data a model for the binding of platelet factor 4 to heparin is proposed. PMID:3718482

  4. Biochemical and functional abnormalities in hypercholesterolemic rabbit platelets

    SciTech Connect

    Dalal, K.B.; Ebbe, S.; Mazoyer, E.; Carpenter, D.; Yee, T. )

    1990-02-01

    This study was designed to elucidate changes in rabbit platelet lipids induced by a cholesterol rich diet and to explore the possible correlation of these lipid changes with platelet abnormalities. Pronounced biochemical alterations were observed when serum cholesterol levels of 700-1000 mg% were reached. Hypercholesterolemic (HC) platelets contained 37% more neutral lipids and 16% less phospholipids than the controls. Lysolecithin, cholesterol esters and phosphatidylinositol (PI) levels were increased in HC platelets, and the levels of phosphatidylcholine (PC) were decreased. The cholesterol/phospholipid molar ratio of lipidemic platelets increased from 0.55 +/- 0.011 to 0.89 +/- 0.016 (P less than 0.01) in eight weeks. HC platelets had 90% more arachidonic acid (AA) in the PI than normal platelets. No significant changes in AA of PC were observed. Platelet function was monitored by the uptake and release of (14C)serotonin in platelet rich plasma (PRP), using varying concentrations of collagen as an aggregating agent. The uptake of (14C)serotonin in HC and normal platelets ranged from 78-94%. The percent of (14C)serotonin released from normal and HC platelets was proportional to the concentration of collagen. However, lipidemic platelets were hyperreactive to low concentrations of collagen. Incorporation of 50 microM acetylsalicylic acid into the aggregating medium suppressed the release of (14C)serotonin in normal PRP by more than 90%, but had only a partial effect on lipidemic PRP.

  5. Insights into Platelet Storage and the Need for Multiple Approaches.

    PubMed

    Handigund, Mallikarjun; Cho, Yong Gon

    2015-01-01

    Upon accidental injury and the treatment of many diseases, patients may need a transfusion of blood components in order to achieve hemostasis. Platelets are small enucleated cells derived from bone marrow megakaryocytes that undergo change upon activation at sites of vascular injury and play a vital role in vascular repair and antimicrobial host defense, collectively contributing to hemostasis. They are the common blood components transfused whenever there is need, but supplies do not equal the demand as platelets are required in many medical and surgical procedures. In addition, surplus supplies of platelet concentrate are often discarded as they have a short shelf life. Currently, platelet concentrates are stored at room temperature for a maximum of 5 days from the date of collection; the temporal aspect is an added hurdle in the growing demand for platelet concentrates. Many investigations have been carried out in attempt to improve the quality and lengthen the shelf life of platelets, but the few that have succeeded are not commercially viable. Moreover, currently there is a declining trend in platelet research, quelling the hope of platelet storage improvement. Successful strategies would be a boon for medicine in particular and humanity in general. This review deals with past and current efforts toward improving the quality of platelet concentrates by reducing platelet storage lesions and increasing the viable storage period for platelets. Also presented are new perspectives based on past and current efforts, which should be investigated for platelet research in this decade. PMID:26663804

  6. Radio-iodobenzylguanidine scintigraphy of neuroblastoma: conflicting results, when compared with standard investigations

    SciTech Connect

    Schmiegelow, K.; Simes, M.A.; Agertoft, L.; Berglund, G.; Storm-Mathisen, I.; Andreassen, M.; Salmi, T.T.; Nygard, R.W.; Wiebe, T.; Kreuger, A.

    1989-01-01

    Seventy-one patients with neuroblastoma (NB) and 25 patients with other neoplastic or nonneoplastic diseases were studied with MIBG scintigraphy. Sensitivity and specificity at diagnosis were 94% and 88%, respectively. Of 52 patients with NB studied during follow-up, 14 had on one or several occasions conflicting results, when the findings at MIBG scintigraphy were compared to standard investigations (SI: CT scan, bone scan, x-ray, and ultrasound). The correlation of MIBG scintigraphy and SI to clinical outcome were in these 14 patients not significantly different. Adding VMA-excretion measurements did not significantly improve the predictive value of MIBG scintigraphy or SI. Patients with tumor-suspected lesions only at MIBG scintigraphy should be followed closely and the nature of the lesions should be explored through biopsy.

  7. Intrahepatic versus extrahepatic cholestasis. Discrimination with biliary scintigraphy combined with ultrasound

    SciTech Connect

    Lieberman, D.A.; Krishnamurthy, G.T.

    1986-03-01

    Biliary scintigraphy and ultrasound imaging were performed in 52 patients with suspected biliary tract pathology. Results were correlated with the findings of direct cholangiography. Several new innovations in scintigraphic technique were used. The combination of ultrasound imaging and scintigraphy correctly identified biliary tract obstruction in 17 of 19 patients, 12 of whom had dilated bile ducts on ultrasonography. Intrahepatic cholestasis was correctly diagnosed in 11 of 13 patients. Accurate discrimination between intrahepatic and extrahepatic cholestasis was achieved in 28 of 32 patients (88%) with the combined studies. Scintigraphy also provided a correct diagnosis of acute cholecystitis in all 9 patients with surgically confirmed disease. Eleven additional patients with gallbladder or pancreatic disease had normal bile ducts at scintigraphy, which was confirmed with cholangiography. When combined with ultrasound imaging, modern biliary scintigraphy can (a) provide excellent discrimination between intrahepatic and extrahepatic cholestasis and (b) help determine the need for subsequent invasive diagnostic studies in selected patients.

  8. Thallium-201 scintigraphy of the suppressed thyroid: an alternative for iodine-123 scanning after TSH stimulation

    SciTech Connect

    Corstens, F.; Huysmans, D.; Kloppenborg, P.

    1988-08-01

    Thallium-201 scintigraphy of the thyroid gland suppressed by autonomous nodule was compared with /sup 123/I scintigraphy after TSH stimulation. In all patients, similar images were obtained by both methods. In 20 patients, the contralateral lobe was visualized on both scans and in 14 of these, the upper pole of the ipsilateral lobe was also visualized. In one patient, neither /sup 123/I scanning after TSH nor /sup 201/TI scintigraphy showed any extranodular tissue. This study suggests that /sup 201/TI scintigraphy is a reliable alternative for scanning after TSH. It is a relatively simple method, not inducing any TSH-related allergic reactions. Iodine uptake in extranodular tissue is not stimulated and therefore, /sup 201/TI scintigraphy and radioiodine therapy can be combined on one day, without increasing the risk of radiation damage to the normal thyroid tissue with a resultant post-treatment hypothyroidism.

  9. The Ratio of ADP- to TRAP-Induced Platelet Aggregation Quantifies P2Y12-Dependent Platelet Inhibition Independently of the Platelet Count

    PubMed Central

    Olivier, Christoph B.; Meyer, Melanie; Bauer, Hans; Schnabel, Katharina; Weik, Patrick; Zhou, Qian; Bode, Christoph; Moser, Martin; Diehl, Philipp

    2016-01-01

    Objective This study aimed to assess the association of clinical factors with P2Y12-dependent platelet inhibition as monitored by the ratio of ADP- to TRAP-induced platelet aggregation and conventional ADP-induced aggregation, respectively. Background Controversial findings to identify and overcome high platelet reactivity (HPR) after coronary stent-implantation and to improve clinical outcome by tailored anti-platelet therapy exist. Monitoring anti-platelet therapy ex vivo underlies several confounding parameters causing that ex vivo platelet aggregation might not reflect in vivo platelet inhibition. Methods In a single centre observational study, multiple electrode aggregometry was performed in whole blood of patients after recent coronary stent-implantation. Relative ADP-induced aggregation (r-ADP-agg) was defined as the ratio of ADP- to TRAP- induced aggregation reflecting the individual degree of P2Y12-mediated platelet reactivity. Results Platelet aggregation was assessed in 359 patients. Means (± SD) of TRAP-, ADP-induced aggregation and r-ADP-agg were 794 ± 239 AU*min, 297 ± 153 AU*min and 37 ± 14%, respectively. While ADP- and TRAP-induced platelet aggregation correlated significantly with platelet count (ADP: r = 0.302; p<0.001; TRAP: r = 0.509 p<0.001), r-ADP-agg values did not (r = -0.003; p = 0.960). These findings were unaltered in multivariate analyses adjusting for a range of factors potentially influencing platelet aggregation. The presence of an acute coronary syndrome and body weight were found to correlate with both ADP-induced platelet aggregation and r-ADP-agg. Conclusion The ratio of ADP- to TRAP-induced platelet aggregation quantifies P2Y12-dependent platelet inhibition independently of the platelet count in contrast to conventional ADP-induced aggregation. Furthermore, r-ADP-agg was associated with the presence of an acute coronary syndrome and body weight as well as ADP-induced aggregation. Thus, the r-ADP-agg is a more valid

  10. Platelet-adenovirus vs. inert particles interaction: effect on aggregation and the role of platelet membrane receptors.

    PubMed

    Gupalo, Elena; Kuk, Cynthia; Qadura, Mohammad; Buriachkovskaia, Liudmila; Othman, Maha

    2013-01-01

    Platelets are involved in host defense via clearance of bacteria from the circulation, interaction with virus particles, and uptake of various size particulates. There is a growing interest in micro- and nanoparticles for drug delivery and there is evidence that the properties of these particles critically influence their interaction and uptake by various tissues and cells including platelets. Virus mediated gene therapy applications are still challenged by the resultant thrombocytopenia and the mechanism(s) of platelet-foreign particles interaction remains unclear. We studied the specifics of platelet interaction with an active biological agent (adenovirus) and inert latex microspheres (MS) and investigated the role of platelet proteins in this interaction. We show that activated and not resting platelets internalize MS, without influencing platelet aggregation. In contrast, adenovirus induces and potentiates ADP-induced platelet aggregation and results in rapid expression of P-selectin. Platelets then internalize adenovirus and viral particles appear inside the open canalicular system. Inhibition of platelet αIIbβ3, GPIbα, and P-selectin decreases both platelet aggregation and internalization of MS. Inhibition of αIIbβ3 and αVβ3 does not abolish adenovirus platelet internalization and adenovirus-induced platelet activation is maintained. Our study demonstrates that platelets react differentially with foreign particles and that αIIbβ3 is a key player in platelet engulfing of foreign particles but not in mediating adenovirus internalization. Other platelet candidate molecules remain to be investigated as potential targets for management of adenovirus-induced thrombocytopenia. PMID:22812520

  11. Detection of platelet isoantibodies by (3H)serotonin platelet release and its clinical application to the problem of platelet matching.

    PubMed Central

    Gockerman, J P; Bowman, R P; Conrad, M E

    1975-01-01

    The detection of platelet isoantibodies by the release of (3H)serotonin from platelets has been evaluated. The conditions for optimal release of (3H)serotonin with platelet isoantibodies using a microtechnique have been defined. A group of cardiac surgery patients were followed pre- and post-transfusions, with 48percent developing a positive serotonin release assay. Of these patients, 16percent also had a platelet complement-fixing and/or lymphocytotoxic isoantibody. There was variation in the degree of correlation between (3H)serotonin release and lymphocytotoxicity using individual National Institutes of Health typing serum. The matching obtained between family members by both techniques showed a close correlation when each technique was evaluated separately using the same NIH typing serum. The detection of iso-antibodies in patients with hematological malignancies correlated with the unresponsiveness to unmatched platelet transfusions in 15 out of 17 cases. The use of the patient's isoantibody to matched platelets of family members by (3H)serotonin release correlated well with the clinical response to transfusion with these platelets. The data suggest that (a) platelet isoantibodies can be detected with increased frequency by (3H)serotonin release; (b) (3H)serotonin release is a specific reaction depending on the surface antigen of the platelet; and (c) the method can be used to match compatible family members for platelet transfusions. PMID:1109183

  12. Platelet turnover and kinetics in immune thrombocytopenic purpura: results with autologous 111In-labeled platelets and homologous 51Cr-labeled platelets differ

    SciTech Connect

    Heyns A du, P.; Badenhorst, P.N.; Loetter, M.G.P.; Pieters, H.; Wessels, P.; Kotze, H.F.

    1986-01-01

    Mean platelet survival and turnover were simultaneously determined with autologous 111In-labeled platelets (111In-AP) and homologous 51Cr-labeled platelets (51Cr-HP) in ten patients with chronic immune thrombocytopenic purpura (ITP). In vivo redistribution of the 111In-AP was quantitated with a scintillation camera and computer-assisted image analysis. The patients were divided into two groups: those with splenic platelet sequestration (spleen-liver 111In activity ratio greater than 1.4), and those with diffuse sequestration in the reticuloendothelial system. The latter patients had more severe ITP reflected by pronounced thrombocytopenia, decreased platelet turnover, and prominent early hepatic platelet sequestration. Mean platelet life span estimated with 51Cr-HP was consistently shorter than that of 111In-AP. Platelet turnover determined with 51Cr-HP was thus over-estimated. The difference in results with the two isotope labels was apparently due to greater in vivo elution of 51Cr. Although the limitations of the techniques should be taken into account, these findings indicate that platelet turnover is not always normal or increased in ITP, but is low in severe disease. We suggest that this may be ascribed to damage to megakaryocytes by antiplatelet antibody. The physical characteristics in 111In clearly make this radionuclide superior to 51Cr for the study of platelet kinetics in ITP.

  13. Accuracy of platelet counting by automated hematologic analyzers in acute leukemia and disseminated intravascular coagulation: potential effects of platelet activation.

    PubMed

    Kim, Seon Young; Kim, Ji-Eun; Kim, Hyun Kyung; Han, Kyou-Sup; Toh, Cheng Hock

    2010-10-01

    Platelet counting in patients with acute leukemia or disseminated intravascular coagulation (DIC) may have a risk for erroneous counts owing to the presence of nonplatelet particles or platelet activation. We evaluated automated platelet counting methods using the Abbott Cell-Dyn Sapphire (Abbott Diagnostics, Santa Clara, CA), Sysmex XE-2100 (Sysmex, Kobe, Japan), ADVIA 2120 (Siemens Diagnostics, Tarrytown, NY), and Beckman Coulter LH 750 (Beckman Coulter, Miami, FL) compared with the international reference method (IRM). Automated platelet counting methods were inaccurate compared with the IRM, without evidence of interfering nonplatelet particles. It is interesting that platelet activation markers were associated with DIC severity and erroneous platelet counting, suggesting that platelet activation is a potential source of inaccuracy. Furthermore, the artifactual in vitro platelet activation induced a high degree of intermethod variation in platelet counts. The inaccuracy of automated platelet counts increased the risk for misdiagnosis of DIC. More attention needs to be given to the accuracy of platelet counts, especially in clinical conditions with florid platelet activation. PMID:20855645

  14. Interactions of human blood-platelets with vaccinia

    SciTech Connect

    Vernon, C.E.B.

    1989-01-01

    These investigations were conducted to determine whether vaccinia (strain WR) adsorbs to the human platelet and alters specific platelet activities, namely, the uptake of {sup 14}C-serotonin, the release of {sup 14}C-serotonin and also the release of {sup 14}C-serotonin stimulated by thrombin. Vaccinia did not alter the platelet uptake of {sup 14}C-serotonin. To determine if vaccinia induces a release of {sup 14}C-serotonin from platelets, vaccinia was added to washed or unwashed {sup 14}C-serotonin labeled platelets, and the release of {sup 14}C-Serotonin into the supernatant was measured. Less than 8% of the {sup 14}C-Serotonin was released. The action of vaccinia to alter the platelet release of {sup 14}C-serotonin induced by thrombin was monitored by measuring the radioactivity released from thrombin stimulated {sup 14}C-serotonin labeled platelets incubated with or without vaccinia. Vaccinia inhibited the thrombin induced release of {sup 14}C-serotonin from platelets at a virus to platelet ratios of 5 through 80 plaque forming units (p.f.u.)/platelet. The inhibition was dose dependent. The binding of virus to platelets was determined by a plaque assay of a washed mixture of vaccinia virus and platelets. After inoculation of mixture onto a monolayer of BSC40 cells at a virus to platelet ratio of 0.1 p.f.u./platelet, 50 cell-bound-virus per 130,000-150,000 platelets were enumerated. Vaccinia was observed to inhibit the thrombin induced clot formation of plasma by a thrombin clotting time test. Scanning electron micrographs of the clot formed in the presence of vaccinia revealed a close packed fibrous structure lacking the cross-linked mesh-like pattern seen in a normal clot. Transmission electron micrographs showed an increase in the length and a close packing of the fibrin threads.

  15. Platelets contribute to growth and metastasis in hepatocellular carcinoma.

    PubMed

    Bihari, Chhagan; Rastogi, Archana; Shasthry, Saggere Muralikrishna; Bajpai, Meenu; Bhadoria, Ajeet Singh; Rajesh, S; Mukund, Amar; Kumar, Anupam; Sarin, Shiv K

    2016-09-01

    To determine the association of platelets with hepatocellular carcinoma (HCC) growth and its metastasis. We examined platelets, laboratory, and radiological data of consecutive 420 HCC and 1008 cirrhosis cases. Follow-up information of platelet count in cirrhosis to HCC, pre- to post-therapy, and post-therapy to HCC outcome was analyzed. Cytokine profiling was performed in HCC and cirrhosis (n = 10 each). On the basis of imaging, HCC was divided into six subgroups. Cytosmears of HCC were assessed for platelet clustering around tumor cells. An in vitro Matrigel invasion assay was performed on human HCC cell lines using graded concentration of platelets. Baseline platelet numbers and platelet/lymphocyte ratios (PLRs) were significantly higher (p < 0.001) in HCC than cirrhosis. IL-1, IL-6, FGF, G-CSF, thrombopoietin, and VEGF were higher in HCC than cirrhosis. Platelet counts were increased after HCC conversion of cirrhosis (p < 0.001) and decreased (p < 0.001) after therapy. Platelets and PLR in recurrence cases were higher than in responders at baseline. AFP, PIVKAII, platelets, and PLR increase (p < 0.001 each) with advancement in HCC growth. Multivariate analysis showed platelets (p = 0.002), PLR (p = 0.004), and AFP (p < 0.001) associated with distant metastasis. Platelet clustering seen in 75.7% of HCC group 3, 45% in group 2, and 12.5% in group 1 cases (p < 0.001). Invaded cells in Matrigel assay positively correlated with platelet concentration. Platelets can contribute to the development, growth, invasion, and metastasis of HCC. Rising platelet count after HCC therapy is indicative of incomplete response or recurrence. PMID:27457354

  16. Diagnostic sensitivity of bone scintigraphy for equine stifle disorders.

    PubMed

    Graham, Sarah; Solano, Mauricio; Sutherland-Smith, James; Sato, Amy F; Maranda, Louise

    2015-01-01

    Disorders of the stifle are a common cause of lameness in horses yet the accuracy of scintigraphy for diagnosis of stifle conditions is controversial. The aim of retrospective cross-sectional study was to determine the diagnostic sensitivity (Se) of bone scintigraphy in detecting stifle disease and to determine if two orthogonal scintigraphic images improve diagnostic Se. Horses that underwent scintigraphic examination during a two-year period were included. Horses were divided into two groups: group 1 (N = 23) had lameness that was localized to the stifle by intra-articular analgesia and group 2 (N = 182) had lameness that was localized to a different location. Scintigraphic studies (one image or two images) were independently and retrospectively analyzed by two radiologists (R1 and R2). Sensitivity, specificity (Sp) and predictive values (PV), and were calculated for each type of study (one image or two images) and for each radiologist (R1 or R2). The Se to detect stifle disorders varied between radiologists (29.2% and 20.8%). The Sp was 84.5% and 88.3%. When two images were evaluated a decrease in the positive PV for both readers occurred. The Cohen kappa coefficient (κ) between readers was poor when one image (0.084) or two images (0.117) were evaluated. Findings from this study indicated that bone-phase nuclear scintigraphy is reasonably specific but highly insensitive for detecting lameness originating from the stifle in a diverse population of both normal and affected horses. The addition of a caudal scintigraphic image acquisition did not improve diagnostic sensitivity. PMID:25065687

  17. Perfusion Scintigraphy and Patient Selection for Lung Volume Reduction Surgery

    PubMed Central

    Chandra, Divay; Lipson, David A.; Hoffman, Eric A.; Hansen-Flaschen, John; Sciurba, Frank C.; DeCamp, Malcolm M.; Reilly, John J.; Washko, George R.

    2010-01-01

    Rationale: It is unclear if lung perfusion can predict response to lung volume reduction surgery (LVRS). Objectives: To study the role of perfusion scintigraphy in patient selection for LVRS. Methods: We performed an intention-to-treat analysis of 1,045 of 1,218 patients enrolled in the National Emphysema Treatment Trial who were non–high risk for LVRS and had complete perfusion scintigraphy results at baseline. The median follow-up was 6.0 years. Patients were classified as having upper or non–upper lobe–predominant emphysema on visual examination of the chest computed tomography and high or low exercise capacity on cardiopulmonary exercise testing at baseline. Low upper zone perfusion was defined as less than 20% of total lung perfusion distributed to the upper third of both lungs as measured on perfusion scintigraphy. Measurements and Main Results: Among 284 of 1,045 patients with upper lobe–predominant emphysema and low exercise capacity at baseline, the 202 with low upper zone perfusion had lower mortality with LVRS versus medical management (risk ratio [RR], 0.56; P = 0.008) unlike the remaining 82 with high perfusion where mortality was unchanged (RR, 0.97; P = 0.62). Similarly, among 404 of 1,045 patients with upper lobe–predominant emphysema and high exercise capacity, the 278 with low upper zone perfusion had lower mortality with LVRS (RR, 0.70; P = 0.02) unlike the remaining 126 with high perfusion (RR, 1.05; P = 1.00). Among the 357 patients with non–upper lobe–predominant emphysema (75 with low and 282 with high exercise capacity) there was no improvement in survival with LVRS and measurement of upper zone perfusion did not contribute new prognostic information. Conclusions: Compared with optimal medical management, LVRS reduces mortality in patients with upper lobe–predominant emphysema when there is low rather than high perfusion to the upper lung. PMID:20538961

  18. Point-of-care platelet function tests: detection of platelet inhibition induced by nonopioid analgesic drugs.

    PubMed

    Scharbert, Gisela; Gebhardt, Kristina; Sow, Zacharia; Duris, Monika; Deusch, Engelbert; Kozek-Langenecker, Sibylle

    2007-12-01

    Detection of platelet inhibition is of clinical relevance in the preinterventional risk-benefit assessment in chronic low-back-pain patients scheduled for invasive pain therapy. We evaluated the sensitivity of various point-of-care platelet function tests for the detection of platelet inhibition induced by nonopioid analgesic drugs. After Institutional Review Board approval and informed consent, citrated whole blood from 40 patients with chronic unspecific low back pain was investigated before and 30 min after intravenous infusion of the study medication consisting of diclofenac 75 mg (plus orphenadrin 30 mg; Neodolpasse; Fresenius Kabi Austria GmbH, Austria), parecoxib 40 mg (Dynastat; Pharmacia Europe EEIG, UK), paracetamol 1 g (Perfalgan; Bieffe Medital S.P.A., Italy), or normal saline in a randomized, cross-over, double-blinded, placebo-controlled study. Platelet function was assessed using the PFA-100 platelet function analyzer and thromboelastometry, as well as impedance aggregometry (in the last 17 patients recruited after it became commercially available). Sensitivity for detecting diclofenac-induced platelet inhibition was 85% for the PFA-100 using epinephrine as agonist and 94% for arachidonic acid-induced impedance aggregometry. ADP-induced platelet function tests, as well as cytochalasin D-modified thromboelastometry were unreliable. All tests had a low incidence of false-positive test results after normal saline. Paracetamol and parecoxib had no significant platelet inhibiting effect. The PFA-100 using epinephrine as agonist and arachidonic acid-induced impedance aggregometry are recommended for the detection of cyclooxygenase-I-inhibiting effects of nonsteroidal anti-inflammatory drugs such as diclofenac. Our findings confirm that a single rescue dose of paracetamol and parecoxib has no antiplatelet effect. PMID:17982319

  19. Platelet activation and platelet-leukocyte interaction in dogs naturally infected with Babesia rossi.

    PubMed

    Goddard, Amelia; Leisewitz, Andrew L; Kristensen, Annemarie T; Schoeman, Johan P

    2015-09-01

    Using flow cytometry, platelet-leukocyte aggregate (PLA) formation has previously been documented in dogs with a variety of systemic inflammatory disorders and immune-mediated haemolytic anaemia. Platelet activation and subsequent interaction between platelets and leukocytes are important for regulating innate immunity and systemic inflammation. The objective of this study was to investigate PLA formation in canine babesiosis and to determine whether it was associated with outcome. Blood was collected from 36 client-owned dogs diagnosed with Babesia rossi infection and 15 healthy controls using EDTA as anticoagulant. Activated platelets and PLA formation were detected by measuring surface expression of P-selectin (CD62P) on platelets, monocytes and neutrophils. Of the Babesia-infected dogs, 29 survived and seven died. The percentage of CD62P-positive monocytes was significantly higher (P = 0.036) in the Babesia-infected dogs (54%) than in healthy control dogs (35.3%). However, there were no significant differences between the Babesia-infected and control groups for CD62P-positive platelets (4.9% and 1.2%, respectively) and CD62P-positive neutrophils (28.3% and 17.9%, respectively). The percentage of CD62P-positive monocytes was significantly higher (P = 0.019) in the survivors (58.9%) than in healthy control dogs; however, there were no significant differences between the non-survivors (39.2%) and the controls or between survivors and non-survivors. There were no significant differences between groups for the percentage of CD62P-positive platelets (survivors 4.8%; non-survivors 5.3%; controls 1.2%) or CD62P-positive neutrophils (survivors 31.6%; non-survivors 5.6%; controls 17.9%). In conclusion, Babesia-infected dogs, specifically dogs that survived, had a significantly increased percentage of platelet-monocyte aggregates compared to healthy control dogs. PMID:26088270

  20. Decreased platelet function in aortic valve stenosis: high shear platelet activation then inactivation.

    PubMed Central

    O'Brien, J. R.; Etherington, M. D.; Brant, J.; Watkins, J.

    1995-01-01

    OBJECTIVE--To elucidate the mechanism of the bleeding tendency observed in patients with aortic valve stenosis. DESIGN--A prospective study of high and low shear platelet function tests in vitro in normal controls compared with that in patients with severe aortic valve stenosis with a mean (SD) systolic gradient by Doppler of 75 (18) mm Hg before and at least 4 months after aortic valve replacement. SETTING--District general hospital. RESULTS--The patients showed reduced retention in the high shear platelet function tests. (a) Platelet retention in the filter test was 53.6 (12.6)% in patients with aortic valve stenosis and 84.8 (9.6)% in the controls (P < 0.001). (b) Retention in the glass bead column test was 49.8 (19.2) in the patients and 87.4 (8.7) in the controls (P < 0.001). (c) The standard bleeding time was longer in the patients (P < 0.06). Results of the high shear tests (a, b, and c) after aortic valve replacement were within the normal range. The platelet count was low but within the normal range before surgery and increased postoperatively (P < 0.01). There were no differences in the results of standard clotting tests, plasma and intraplatelet von Willebrand's factor, or in 15 platelet aggregation tests using five agonists between patients with aortic valve stenosis and controls. CONCLUSIONS--The high shear haemodynamics of aortic valve stenosis modify platelet function in vivo predisposing to a bleeding tendency. This abnormality of platelet function is detectable only in vitro using high shear tests. The abnormal function is reversed by aortic valve replacement. High shear forces in vitro activate and then inactivate platelets. By the same mechanisms aortic valve stenosis seems to lead to high shear damage in vivo, resulting in a clinically important bleeding tendency in some patients. PMID:8541170

  1. Formed platelets for low cost regeneratively cooled rocket combustion chambers

    NASA Technical Reports Server (NTRS)

    Burkhardt, W. M.; Hayes, W. A.

    1992-01-01

    Formed platelet technology can be used to fabricate LO2/LH2-fueled rocket propulsion chambers with higher heat capacity, higher cycle life, and lower pressure drops, in conjunction with lower costs due to the application of high volume production methods. The formed-platelet combustor liner is an assembly of identical platelets, each of which is composed of diffusion-bonded, photoetched laminae with coolant flow passages; the platelets are also joined by diffusion bonding to form the combustor's circumference. Attention is given to the fabrication of a platelet combustion chamber generating 40 Klbf of thrust.

  2. Acquired Platelet Dysfunction with Eosinophilia (APDE) Syndrome: A Case Report.

    PubMed

    Yadav, Diksha D; Nayar, Priyanka S; Manchanda, Rumma V

    2016-06-01

    Acquired platelet dysfunction with eosinophilia (APDE) is a syndrome which has transient state of platelet dysfunction in the presence of marked eosinophilia. This bleeding disorder, otherwise known as "non-thrombocytopenic purpura with eosinophilia", occurs commonly in children from South-East Asia. We report an 11 years old male child, who presented with ecchymotic patches over lower limbs, of recent onset. His hemogram revealed increased eosinophils with a normal platelet count. Coagulation screen revealed normal parameters except increase in bleeding time. Platelet aggregation studies showed normal platelet aggregation with ristocetin, reduced aggregation with ADP and no aggregation was seen with collagen. PMID:27408400

  3. The incredible journey: From megakaryocyte development to platelet formation

    PubMed Central

    Machlus, Kellie R.

    2013-01-01

    Circulating blood platelets are specialized cells that prevent bleeding and minimize blood vessel injury. Large progenitor cells in the bone marrow called megakaryocytes (MKs) are the source of platelets. MKs release platelets through a series of fascinating cell biological events. During maturation, they become polyploid and accumulate massive amounts of protein and membrane. Then, in a cytoskeletal-driven process, they extend long branching processes, designated proplatelets, into sinusoidal blood vessels where they undergo fission to release platelets. Given the need for platelets in many pathological situations, understanding how this process occurs is an active area of research with important clinical applications. PMID:23751492

  4. Platelet aggregating material from equine arterial tissue

    SciTech Connect

    Schneider, M.D.

    1983-02-22

    Novel hemostatic agent comprises equine arterial fibrillar collagen in a carrier. The agent is useful for the aggregation of platelets for clinical diagnostic tests and for the clotting of blood, such as for controlling bleeding in warm blooded species. The fibrillar collagen is obtained by extracting homogenized equine arterial tissue with aqueous solutions followed by extensive dialysis. No Drawings

  5. Platelet aggregating material from equine arterial tissue

    SciTech Connect

    Schneider, Morris D.

    1983-02-22

    Novel hemostatic agent comprises equine arterial fibrillar collagen in a carrier. The agent is useful for the aggregation of platelets for clinical diagnostic tests and for the clotting of blood, such as for controlling bleeding in warm blooded species. The fibrillar collagen is obtained by extracting homogenized equine arterial tissue with aqueous solutions followed by extensive dialysis.

  6. Increased Mean Platelet Volume in Familial Hypercholesterolemia.

    PubMed

    Icli, Atilla; Aksoy, Fatih; Nar, Gökay; Kaymaz, Haci; Alpay, Mehmet Fatih; Nar, Rukiye; Guclu, Aydın; Arslan, Akif; Dogan, Abdullah

    2016-02-01

    Familial hypercholesterolemia (FH) is a genetic disorder of lipoprotein metabolism and increases the risk of premature cardiovascular diseases. In patients with FH, platelet function may be activated; however, the extent of this activation and its etiology are unclear. We aimed to evaluate the mean platelet volume (MPV), a marker of platelet activation, in patients with FH. The study group consisted of 164 patients with FH and 160 control patients. Controls were matched for age, gender, hypertension, and smoking. The MPV was significantly higher in patients with FH than in controls (9.2 ± 0.4 vs 7.9 ± 0.6 fL, respectively; P < .001). Platelet count was significantly lower among patients with FH when compared to control patients (259 ± 51 vs 272 ± 56 × 10(3)/L, respectively; P = .03). In linear regression analysis, MPV was independently associated only with total cholesterol (β = .6, 95% confidence interval: 0.004-0.008, P < .001). We have shown that MPV was increased in patients with FH and that it was independently associated with total cholesterol level. PMID:25859052

  7. Citrate bridges between mineral platelets in bone.

    PubMed

    Davies, Erika; Müller, Karin H; Wong, Wai Ching; Pickard, Chris J; Reid, David G; Skepper, Jeremy N; Duer, Melinda J

    2014-04-01

    We provide evidence that citrate anions bridge between mineral platelets in bone and hypothesize that their presence acts to maintain separate platelets with disordered regions between them rather than gradual transformations into larger, more ordered blocks of mineral. To assess this hypothesis, we take as a model for a citrate bridging between layers of calcium phosphate mineral a double salt octacalcium phosphate citrate (OCP-citrate). We use a combination of multinuclear solid-state NMR spectroscopy, powder X-ray diffraction, and first principles electronic structure calculations to propose a quantitative structure for this material, in which citrate anions reside in a hydrated layer, bridging between apatitic layers. To assess the relevance of such a structure in native bone mineral, we present for the first time, to our knowledge, (17)O NMR data on bone and compare them with (17)O NMR data for OCP-citrate and other calcium phosphate minerals relevant to bone. The proposed structural model that we deduce from this work for bone mineral is a layered structure with thin apatitic platelets sandwiched between OCP-citrate-like hydrated layers. Such a structure can explain a number of known structural features of bone mineral: the thin, plate-like morphology of mature bone mineral crystals, the presence of significant quantities of strongly bound water molecules, and the relatively high concentration of hydrogen phosphate as well as the maintenance of a disordered region between mineral platelets. PMID:24706850

  8. Platelets and the complement cascade in atherosclerosis

    PubMed Central

    Patzelt, Johannes; Verschoor, Admar; Langer, Harald F.

    2015-01-01

    Atherosclerosis and its late sequels are still the number one cause of death in western societies. Platelets are a driving force not only during the genesis of atherosclerosis, but especially in its late stages, as evidenced by complications such as arterial thrombosis, myocardial infarction, and ischemic stroke. Atherosclerosis is increasingly recognized as an inflammatory disease, influenced by various immune mechanisms. The complement system is part of our innate immune system, and its diverse roles in atherosclerosis have become evident over the past years. In this review we identify points of intersection between platelets and the complement system and discuss their relevance for atherosclerosis. Specifically, we will focus on roles for platelets in the onset as well as progression of the disease, a possible dual role for complement in the genesis and development of atherosclerosis, and review emerging literature revealing previously unrecognized cross-talk between platelets and the complement system and discuss its possible impact for atherosclerosis. Finally, we identify limitations of current research approaches and discuss perspectives of complement modulation in the control of the disease. PMID:25784879

  9. Sports medicine applications of platelet rich plasma.

    PubMed

    Mishra, Allan; Harmon, Kimberly; Woodall, James; Vieira, Amy

    2012-06-01

    Platelet rich plasma (PRP) is a powerful new biologic tool in sports medicine. PRP is a fraction of autologous whole blood containing and increased number of platelets and a wide variety of cytokines such as platelet derived growth factor (PDGF), vascular endothelial growth factor (VEGF) and transforming growth factor beta-1 (TGF-B1), fibroblast growth factor (FGF), Insulin-like growth factor-1 (IGF-1) among many others. Worldwide interest in this biologic technology has recently risen sharply. Basic science and preclinical data support the use of PRP for a variety of sports related injuries and disorders. The published, peer reviewed, human data on PRP is limited. Although the scientific evaluation of clinical efficacy is in the early stages, elite and recreational athletes already use PRP in the treatment of sports related injuries. Many questions remain to be answered regarding the use of PRP including optimal formulation, including of leukocytes, dosage and rehabilitation protocols. In this review, a classification for platelet rich plasma is proposed and the in-vitro, preclinical and human investigations of PRP applications in sports medicine will be reviewed as well as a discussion of rehabilitation after a PRP procedure. The regulation of PRP by the World Anti-Doping Agency will also be discussed. PRP is a promising technology in sports medicine; however, it will require more vigorous study in order to better understand how to apply it most effectively. PMID:21740373

  10. Epithelial sodium channel modulates platelet collagen activation.

    PubMed

    Cerecedo, Doris; Martínez-Vieyra, Ivette; Alonso-Rangel, Lea; Benítez-Cardoza, Claudia; Ortega, Arturo

    2014-03-01

    Activated platelets adhere to the exposed subendothelial extracellular matrix and undergo a rapid cytoskeletal rearrangement resulting in shape change and release of their intracellular dense and alpha granule contents to avoid hemorrhage. A central step in this process is the elevation of the intracellular Ca(2+) concentration through its release from intracellular stores and on throughout its influx from the extracellular space. The Epithelial sodium channel (ENaC) is a highly selective Na(+) channel involved in mechanosensation, nociception, fluid volume homeostasis, and control of arterial blood pressure. The present study describes the expression, distribution, and participation of ENaC in platelet migration and granule secretion using pharmacological inhibition with amiloride. Our biochemical and confocal analysis in suspended and adhered platelets suggests that ENaC is associated with Intermediate filaments (IF) and with Dystrophin-associated proteins (DAP) via α-syntrophin and β-dystroglycan. Migration assays, quantification of soluble P-selectin, and serotonin release suggest that ENaC is dispensable for migration and alpha and dense granule secretion, whereas Na(+) influx through this channel is fundamental for platelet collagen activation. PMID:24679405

  11. Pneumolysin Mediates Platelet Activation In Vitro.

    PubMed

    Nel, Jan Gert; Durandt, Chrisna; Mitchell, Timothy J; Feldman, Charles; Anderson, Ronald; Tintinger, Gregory R

    2016-08-01

    This study has explored the role of the pneumococcal toxin, pneumolysin (Ply), in activating human platelets. Following exposure to Ply (10-80 ng/ml), platelet activation and cytosolic Ca(2+) concentrations were measured flow cytometrically according to the level of expression of CD62P (P-selectin) and spectrofluorimetrically, respectively. Exposure to Ply resulted in marked upregulation of expression of platelet CD62P, achieving statistical significance at concentrations of 40 ng/ml and higher (P < 0.05), in the setting of increased influx of Ca(2+). These potentially pro-thrombotic actions of Ply were attenuated by depletion of Ca(2+) from the extracellular medium or by exposure of the cells to a pneumolysoid devoid of pore-forming activity. These findings are consistent with a mechanism of Ply-mediated platelet activation involving sub-lytic pore formation, Ca(2+) influx, and mobilization of CD62P-expressing α-granules, which, if operative in vivo, may contribute to the pathogenesis of associated acute lung and myocardial injury during invasive pneumococcal disease. PMID:27192991

  12. 21 CFR 864.6675 - Platelet aggregometer.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Platelet aggregometer. 864.6675 Section 864.6675 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Manual Hematology Devices § 864.6675...

  13. 21 CFR 864.6675 - Platelet aggregometer.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Platelet aggregometer. 864.6675 Section 864.6675 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Manual Hematology Devices § 864.6675...

  14. 21 CFR 864.6675 - Platelet aggregometer.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Platelet aggregometer. 864.6675 Section 864.6675 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Manual Hematology Devices § 864.6675...

  15. 21 CFR 864.6675 - Platelet aggregometer.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Platelet aggregometer. 864.6675 Section 864.6675 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Manual Hematology Devices § 864.6675...

  16. 21 CFR 864.6675 - Platelet aggregometer.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Platelet aggregometer. 864.6675 Section 864.6675 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Manual Hematology Devices § 864.6675...

  17. Animating platelet production adds physiological context

    PubMed Central

    Thon, Jonathan N.; Kitterman, Alice C.; Italiano, Joseph E.

    2015-01-01

    Animating complex biological processes contextualizes them within their underlying physiology, identifies gaps in our mechanistic understanding, affirms the importance of continued research, and provides a bridge between academic scientists and the general public. Here, two videos illustrate the clinical value of and translate state-of-the-art research in platelet production. PMID:23953478

  18. Collagen-platelet interactions: recognition and signalling.

    PubMed

    Farndale, Richard W; Siljander, Pia R; Onley, David J; Sundaresan, Pavithra; Knight, C Graham; Barnes, Michael J

    2003-01-01

    The collagen-platelet interaction is central to haemostasis and may be a critical determinant of arterial thrombosis, where subendothelium is exposed after rupture of atherosclerotic plaque. Recent research has capitalized on the cloning of an important signalling receptor for collagen, glycoprotein VI, which is expressed only on platelets, and on the use of collagen-mimetic peptides as specific tools for both glycoprotein VI and integrin alpha 2 beta 1. We have identified sequences, GPO and GFOGER (where O denotes hydroxyproline), within collagen that are recognized by the collagen receptors glycoprotein VI and integrin alpha 2 beta 1 respectively, allowing their signalling properties and specific functional roles to be examined. Triple-helical peptides containing these sequences were used to show the signalling potential of integrin alpha 2 beta 1, and to confirm its important contribution to platelet adhesion. Glycoprotein VI appears to operate functionally on the platelet surface as a dimer, which recognizes GPO motifs that are separated by four triplets of collagen sequence. These advances will allow the relationship between the structure of collagen and its haemostatic activity to be established. PMID:14587284

  19. Mean platelet volume measurement, EDTA or citrate?

    PubMed

    Dastjerdi, Mansour Siavash; Emami, Tajolmolouk; Najafian, Alireza; Amini, Masoud

    2006-10-01

    Most laboratories use EDTA for anticoagulation of whole blood prior to automated cell counting but due to platelet swelling, mean platelet volume (MPV) values may increase with its use. MPV changes may be less with acid citrate based anticoagulation. As MPV is a marker of platelet function and its precise measurement is important in a number of clinical situations, this study was performed to assess if EDTA and citrate based anticoagulated blood samples can be used interchangeably for MPV measurement. In this cross sectional descriptive study, EDTA and citrate based anticoagulated blood samples of the same patients were assessed by auto-analyzer within 1 h of sampling. In the 61 evaluated patients, there was a close correlation between MPV as measured by EDTA and citrate, but mean MPV measured from EDTA samples was 0.66 fL (9%) more than citrate. There was also a significant negative correlation between platelets count and MPV by both methods. The results of our study reveal that MPV can be measured accurately by both methods of anticoagulation; EDTA and citrate if analysis be performed within 1 h of sampling. PMID:17607580

  20. A computerized multichannel platelet aggregometer system.

    PubMed

    Kuzara, D; Zoltan, B J; Greathouse, S L; Jordan, C W; Kohler, C A

    1986-08-01

    Commercially available instrumentation for conducting platelet aggregation studies in clinical and research laboratories consists of one-, two-, or four-channel aggregometers used in conjunction with strip chart recorders. These instruments have limited utility in large-scale drug screening and evaluation of the mode of action of drugs or in the clinical diagnosis of platelet disorders. A new instrument, a computerized multichannel aggregometer system (CMPAS) has been developed to collect, display, and analyze platelet aggregation data. The system is comprised of a 24-channel Born-type aggregometer, interfaced to a Rockwell AIM-65 microcomputer through an analogue-to-digital converter and an Epson dot-matrix printer. Each channel is individually calibrated, and aggregation data can be collected on up to 24 different platelet-rich plasma samples simultaneously. Conversational programs written in BASIC prompt the user for the addition of agonists and inhibitors. The tracings for each channel are displayed simultaneously, and a program automatically analyzes the data to generate the following parameters: baseline optical density, maximum aggregation response, positive and negative slopes, time to peak aggregation, and percentage response. Computerized multichannel aggregometer system data outputs are comparable to data generated by a standard Chronolog aggregometer unit. The advantages of the system include multichannel capability, simultaneous display of all channels allowing relative comparisons between control and experimental groups, and time savings and improved efficiency in conducting and analyzing aggregation experiments. PMID:3755779

  1. Rare case of thoracic kidney detected by renal scintigraphy.

    PubMed

    Natarajan, Aravintho; Agrawal, Archi; Purandare, Nilendu; Shah, Sneha; Rangarajan, Venkatesh

    2016-01-01

    Intrathoracic kidney is a rare congenital abnormality with lowest frequency among all renal ectopias. Patients with thoracic kidneys are usually asymptomatic, and the condition is usually discovered incidentally during radiological evaluation for other conditions or during thoracic surgery. We report a case of a 62-year-old male who was referred to our department for renal scintigraphy for a nonvisualized left kidney on ultrasonography report. Both Tc-99m dimercaptosuccinic acid and diethylenetriaminepentaacetic acid scans revealed a left thoracic kidney which was confirmed by CT scan of the thorax and abdomen. PMID:27385896

  2. Rare case of thoracic kidney detected by renal scintigraphy

    PubMed Central

    Natarajan, Aravintho; Agrawal, Archi; Purandare, Nilendu; Shah, Sneha; Rangarajan, Venkatesh

    2016-01-01

    Intrathoracic kidney is a rare congenital abnormality with lowest frequency among all renal ectopias. Patients with thoracic kidneys are usually asymptomatic, and the condition is usually discovered incidentally during radiological evaluation for other conditions or during thoracic surgery. We report a case of a 62-year-old male who was referred to our department for renal scintigraphy for a nonvisualized left kidney on ultrasonography report. Both Tc-99m dimercaptosuccinic acid and diethylenetriaminepentaacetic acid scans revealed a left thoracic kidney which was confirmed by CT scan of the thorax and abdomen. PMID:27385896

  3. Papillary carcinoma in ectopic thyroid detected by Tl-201 scintigraphy

    SciTech Connect

    Michigishi, T.; Mizukami, Y.; Mura, T.; Nomura, T.; Watanabe, K.; Tonami, N.; Hisada, K. )

    1991-05-01

    A 37-year-old man with papillary carcinoma in an ectopic thyroid is presented. Excisional biopsy revealed the cervical mass to be a metastasis from thyroid cancer. X-ray, ultrasonography, and computed tomography, however, failed to identify the primary tumor in the thyroid. Incidental TI-201 uptake was noted in the midline of the anterior neck, and a palpable nodule was discovered in this area. Fine needle aspiration cytology demonstrated Class V papillary adenocarcinoma, and subsequent surgery confirmed a papillary carcinoma in the ectopic thyroid. This case suggests the usefulness of TI-201 scintigraphy for the detection of ectopic thyroid malignancy.

  4. Femoroacetabular impingement mimicking avascular osteonecrosis on bone scintigraphy

    PubMed Central

    Suarez, Juan Pablo; Domínguez, María Luz; Nogareda, Zulema; Gómez, María Asunción; Muñoz, Jose

    2016-01-01

    Femoroacetabular impingement (FAI) is a structural abnormality of proximal femur and/or acetabulum. It has been recently described, and there are limited reports in nuclear medicine literature because bone scintigraphy is not listed in its diagnostic protocol, but it should be included on differential diagnosis when evaluating patients, with hip-related symptoms because it may be misinterpreted as degenerative changes or avascular necrosis, and its early treatment avoid progression to osteoarthritis. We describe the case of a male who suffered from hip pain. Bone planar scintigraphic appearance mimicked avascular necrosis, but single photon emission computed tomography (CT) imaging and CT examination confirmed the diagnosis of FAI. PMID:27095871

  5. Hepatobiliary scintigraphy in patients receiving hepatic artery infusion chemotherapy

    SciTech Connect

    Housholder, D.F.; Hynes, H.E.; Dakhil, S.R.; Marymont, J.V.

    1985-05-01

    Hepatic artery infusion chemotherapy is used in the treatment of certain selected hepatic tumors, especially metastatic adenocarcinoma of the colon. Chemical cholecystitis has been recognized recently as a complication of hepatic artery infusion chemotherapy. The authors performed hepatobiliary scans on ten patients receiving hepatic artery infusion chemotherapy. All ten patients had abnormal hepatobiliary scintigraphy. They present case reports of three patients with abnormal hepatobiliary scans who have required cholecystectomy for symptoms of chemical cholecystitis to illustrate the clinical, scintigraphic, and pathologic findings in these patients.

  6. Malignant external otitis: The diagnostic value of bone scintigraphy

    SciTech Connect

    Ostfeld, E.; Aviel, A.; Pelet, D.

    1981-06-01

    Technetium99m Methylene Diphosphate bone scintigraphy (BS) of the skull was performed in three patients with malignant external otitis (MEO). Pathological uptake of the radioisotope in the mastoid region was found during the early stages of MEO updating radiologic findings. The extent of the radioisotope accumulation during the early stages of MEO indicates that the actual tissue damage exceeds the clinical estimation. The follow-up BS findings correlate well with the clinical course of MEO indicating either healing or extension to the base of skull.

  7. Bone Scintigraphy in the Diagnosis of Rheumatoid Arthritis: Is There Additional Value of Bone Scintigraphy with Blood Pool Phase over Conventional Bone Scintigraphy?

    PubMed

    Kim, Ji Young; Choi, Yun Young; Kim, Chan Woo; Sung, Yoon-Kyoung; Yoo, Dae-Hyun

    2016-04-01

    We aimed to investigate the value of bone scintigraphy with additional blood pool phase (BSBP), compared with conventional bone scintigraphy (CBS), in the assessment of rheumatoid arthritis (RA). A total of 242 patients (43 males, 199 females; 14-78 years) with arthralgia, and underwent BSBP were retrospectively analyzed. On the first physical examination, active arthritis was found in 128 of the 242 patients. Clinical diagnosis was made by a rheumatologist on the basis of the 1987 American College of Rheumatology (ACR) criteria, which are considered to be the gold standard. The diagnostic performances and prognostic value of BSBP and CBS were analyzed in the total patients with arthralgia and in the patients with arthritis. The sensitivity of BSBP (84.2%, 80/95) were significantly higher than that of CBS (74.8%, 72/95) in the patients with arthralgia (P = 0.039). When BSBP was interpreted with the results of elevated/positive anti-CCP antibody, its accuracy over CBS also became significantly higher (86.0%, 208/242 vs. 83.1%, 201/242 respectively, P = 0.021). The diagnostic odds ratio of BSBP positivity was higher than CBS positivity in the patients with arthralgia (26.0, 12.9-52.4 vs. 21.1, 10.8-41.3) and with arthritis (12.0, 4.9-29.4 vs. 10.0, 4.2-23.4). Both BSBP and CBS appear to provide acceptable accuracy and comparable diagnostic performance for diagnosis of RA. However, in the patients with arthralgia, BSBP was found to be more sensitive than CBS and more accurate when interpreted with the result of anti-CCP antibody. This could help physicians diagnose RA in daily clinical practice. PMID:27051232

  8. Bone Scintigraphy in the Diagnosis of Rheumatoid Arthritis: Is There Additional Value of Bone Scintigraphy with Blood Pool Phase over Conventional Bone Scintigraphy?

    PubMed Central

    2016-01-01

    We aimed to investigate the value of bone scintigraphy with additional blood pool phase (BSBP), compared with conventional bone scintigraphy (CBS), in the assessment of rheumatoid arthritis (RA). A total of 242 patients (43 males, 199 females; 14–78 years) with arthralgia, and underwent BSBP were retrospectively analyzed. On the first physical examination, active arthritis was found in 128 of the 242 patients. Clinical diagnosis was made by a rheumatologist on the basis of the 1987 American College of Rheumatology (ACR) criteria, which are considered to be the gold standard. The diagnostic performances and prognostic value of BSBP and CBS were analyzed in the total patients with arthralgia and in the patients with arthritis. The sensitivity of BSBP (84.2%, 80/95) were significantly higher than that of CBS (74.8%, 72/95) in the patients with arthralgia (P = 0.039). When BSBP was interpreted with the results of elevated/positive anti-CCP antibody, its accuracy over CBS also became significantly higher (86.0%, 208/242 vs. 83.1%, 201/242 respectively, P = 0.021). The diagnostic odds ratio of BSBP positivity was higher than CBS positivity in the patients with arthralgia (26.0, 12.9-52.4 vs. 21.1, 10.8-41.3) and with arthritis (12.0, 4.9-29.4 vs. 10.0, 4.2-23.4). Both BSBP and CBS appear to provide acceptable accuracy and comparable diagnostic performance for diagnosis of RA. However, in the patients with arthralgia, BSBP was found to be more sensitive than CBS and more accurate when interpreted with the result of anti-CCP antibody. This could help physicians diagnose RA in daily clinical practice. PMID:27051232

  9. Cross-match-compatible platelets improve corrected count increments in patients who are refractory to randomly selected platelets

    PubMed Central

    Elhence, Priti; Chaudhary, Rajendra K.; Nityanand, Soniya

    2014-01-01

    Background Cross-match-compatible platelets are used for the management of thrombocytopenic patients who are refractory to transfusions of randomly selected platelets. Data supporting the effectiveness of platelets that are compatible according to cross-matching with a modified antigen capture enzyme-linked immunosorbent assay (MAC-ELISA or MACE) are limited. This study aimed to determine the effectiveness of cross-match-compatible platelets in an unselected group of refractory patients. Materials and methods One hundred ABO compatible single donor platelet transfusions given to 31 refractory patients were studied. Patients were defined to be refractory if their 24-hour corrected count increment (CCI) was <5×109/L following two consecutive platelet transfusions. Platelets were cross-matched by MACE and the CCI was determined to monitor the effectiveness of platelet transfusions. Results The clinical sensitivity, specificity, positive predictive value and negative predictive value of the MACE-cross-matched platelets for post-transfusion CCI were 88%, 54.6%, 39.3% and 93.2%, respectively. The difference between adequate and inadequate post-transfusion 24-hour CCI for MACE cross-matched-compatible vs incompatible single donor platelet transfusions was statistically significant (p=0.000). The 24-hour CCI (mean±SD) was significantly higher for cross-match-compatible platelets (9,250±026.6) than for incompatible ones (6,757.94±2,656.5) (p<0.0001). Most of the incompatible cross-matches (73.2%) were due to anti-HLA antibodies, alone (55.3% of cases) or together with anti-platelet glycoprotein antibodies (17.9%). Discussion The clinical sensitivity and negative predictive value of platelet cross-matching by MACE were high in this study and such tests may, therefore, be used to select compatible platelets for refractory patients. A high negative predictive value demonstrates the greater chance of an adequate response with cross-matched-compatible platelets. PMID

  10. Platelet antibody detection by flow cytometry: an effective method to evaluate and give transfusional support in platelet refractoriness

    PubMed Central

    Bub, Carolina Bonet; Martinelli, Beatriz Moraes; Avelino, Thayná Mendonça; Gonçalez, Ana Cláudia; Barjas-Castro, Maria de Lourdes; Castro, Vagner

    2013-01-01

    Background Immune platelet refractoriness is mainly caused by human leukocyte antigen antibodies (80-90% of cases) and, to a lesser extent, by human platelet antigen antibodies. Refractoriness can be diagnosed by laboratory tests and patients should receive compatible platelet transfusions. A fast, effective and low cost antibody-screening method which detects platelet human leukocyte/platelet antigen antibodies is essential in the management of immune platelet refractoriness. Objective The aim of this study was to evaluate the efficiency of the flow cytometry platelet immunofluorescence test to screen for immune platelet refractoriness. Methods A group of prospective hematologic patients with clinically suspected platelet refractoriness treated in a referral center in Campinas, SP during July 2006 and July 2011 was enrolled in this study. Platelet antibodies were screened using the flow cytometry platelet immunofluorescence test. Anti-human leukocyte antigen antibodies were detected by commercially available methods. The sensitivity, specificity and predictive values of the immunofluorescence test were determined taking into account that the majority of antiplatelet antibodies presented human leukocyte antigen specificity. Results Seventy-six samples from 32 female and 38 male patients with a median age of 43.5 years (range: 5-84 years) were analyzed. The sensitivity of the test was 86.11% and specificity 75.00% with a positive predictive value of 75.61% and a negative predictive value of 85.71%. The accuracy of the method was 80.26%. Conclusion This study shows that the flow cytometry platelet immunofluorescence test has a high correlation with the anti-human leukocyte antigen antibodies. Despite a few limitations, the method seems to be efficient, fast and feasible as the initial screening for platelet antibody detection and a useful tool to crossmatch platelets for the transfusional support of patients with immune platelet refractoriness. PMID:24106442

  11. Unaltered Angiogenesis-Regulating Activities of Platelets in Mild Type 2 Diabetes Mellitus despite a Marked Platelet Hyperreactivity.

    PubMed

    Miao, Xinyan; Zhang, Wei; Huang, Zhangsen; Li, Nailin

    2016-01-01

    Type 2 diabetes mellitus (T2DM) is associated with platelet dysfunction and impaired angiogenesis. Aim of the study is to investigate if platelet dysfunction might hamper platelet angiogenic activities in T2DM patients. Sixteen T2DM patients and gender/age-matched non-diabetic controls were studied. Flow cytometry and endothelial colony forming cell (ECFC) tube formation on matrigel were used to assess platelet reactivity and angiogenic activity, respectively. Thrombin receptor PAR1-activating peptide (PAR1-AP) induced higher platelet P-selectin expression, and evoked more rapid and intense platelet annexin V binding in T2DM patients, seen as a more rapid increase of annexin V+ platelets (24.3±6.4% vs 12.6±3.8% in control at 2 min) and a higher elevation (30.9±5.1% vs 24.3±3.0% at 8 min). However, PAR1-AP and PAR4-AP induced similar releases of angiogenic regulators from platelets, and both stimuli evoked platelet release of platelet angiogenic regulators to similar extents in T2DM and control subjects. Thus, PAR1-stimulated platelet releasate (PAR1-PR) and PAR4-PR similarly enhanced capillary-like network/tube formation of ECFCs, and the enhancements did not differ between T2DM and control subjects. Direct supplementation of platelets to ECFCs at the ratio of 1:200 enhanced ECFC tube formation even more markedly, leading to approximately 100% increases of the total branch points of ECFC tube formation, for which the enhancements were also similar between patients and controls. In conclusion, platelets from T2DM subjects are hyperreactive. Platelet activation induced by high doses of PAR1-AP, however, results in similar releases of angiogenic regulators in mild T2DM and control subjects. Platelets from T2DM and control subjects also demonstrate similar enhancements on ECFC angiogenic activities. PMID:27612088

  12. Quantitation of microparticles released from coated-platelets.

    PubMed

    Dale, G L; Remenyi, G; Friese, P

    2005-09-01

    Dual agonist stimulation of platelets with thrombin and convulxin results in generation of coated-platelets, a sub-population of cells known formerly as COAT-platelets (collagen and thrombin). Coated-platelets retain several procoagulant proteins on their surface and express phosphatidylserine (PS). In this report, we utilize a new methodology to demonstrate that coated-platelets also release microparticles. Platelets were prelabeled with 2.5 microm Bodipy-maleimide and then stimulated with convulxin plus thrombin. Microparticles, 0.3-0.5 microm in diameter, were observed by fluorescence confocal microscopy. Confocal microscopy was also used to demonstrate that microparticles were positive for glycoprotein IIb/IIIa, glycoprotein Ib, CD9, and PS, but negative for fibrinogen and thrombospondin. Furthermore, microparticles released from Bodipy-labeled platelets were observed by flow cytometry, and activation with convulxin plus thrombin produced 15 +/- 5 microparticles per coated-platelet. In contrast, platelets stimulated with thrombin or convulxin alone produced few microparticles. Phenylarsine oxide and diamide, both of which potentiate the mitochondrial permeability transition pore and coated-platelet production, significantly increased the number of microparticles released per coated-platelet. PMID:16102115

  13. Ex vivo production of platelets from stem cells.

    PubMed

    Avanzi, Mauro P; Mitchell, William Beau

    2014-04-01

    Stem cell technology holds great promise for transfusion medicine, and generation of platelets from stem cells would be transformative. Platelet transfusions are life saving for millions of people and the clinical demand for platelets continues to increase: there is a real need to increase the supply of platelets. Accordingly, there is great interest in the potential of producing platelets from stem cells for clinical use. There has been initial success in ex vivo generation of platelets from stem cells using cord blood stem cells, embryonic stem cells and induced pluripotent stem cells. However, the platelet yields achieved by these strategies have not been sufficient for clinical purposes. This review provides updated information about the current strategies of ex vivo generation of platelets. Megakaryocytopoiesis and platelet generation, along with the importance of genetic determinants of these processes, are reviewed in the context of efforts to generate these products from stem cells. Current challenges and rate-limiting steps in ex vivo platelet generation are discussed, together with strategies to overcome them. While much work remains, great progress has been made, moving ex vivo generation of platelets ever closer to the clinic. PMID:24521452

  14. Improving platelet transfusion safety: biomedical and technical considerations.

    PubMed

    Garraud, Olivier; Cognasse, Fabrice; Tissot, Jean-Daniel; Chavarin, Patricia; Laperche, Syria; Morel, Pascal; Lefrère, Jean-Jacques; Pozzetto, Bruno; Lozano, Miguel; Blumberg, Neil; Osselaer, Jean-Claude

    2016-03-01

    Platelet concentrates account for near 10% of all labile blood components but are responsible for more than 25% of the reported adverse events. Besides factors related to patients themselves, who may be particularly at risk of side effects because of their underlying illness, there are aspects of platelet collection and storage that predispose to adverse events. Platelets for transfusion are strongly activated by collection through disposal equipment, which can stress the cells, and by preservation at 22 °C with rotation or rocking, which likewise leads to platelet activation, perhaps more so than storage at 4 °C. Lastly, platelets constitutively possess a very large number of bioactive components that may elicit pro-inflammatory reactions when infused into a patient. This review aims to describe approaches that may be crucial to minimising side effects while optimising safety and quality. We suggest that platelet transfusion is complex, in part because of the complexity of the "material" itself: platelets are highly versatile cells and the transfusion process adds a myriad of variables that present many challenges for preserving basal platelet function and preventing dysfunctional activation of the platelets. The review also presents information showing--after years of exhaustive haemovigilance--that whole blood buffy coat pooled platelet components are extremely safe compared to the gold standard (i.e. apheresis platelet components), both in terms of acquired infections and of immunological/inflammatory hazards. PMID:26674828

  15. Geometric complexity is increased in in vitro activated platelets.

    PubMed

    Bianciardi, Giorgio

    2015-06-01

    This article investigates the use of computerized fractal analysis for objective characterization of the complexity of platelets in vitro stimulated by low level thrombin (0.02 U mL(-1) ), collected from healthy individuals and observed by means of transmission electron microscopy. Platelet boundaries were extracted by means of automatically image analysis. Local fractal dimension was evaluated by the box-counting technique (measure of geometric complexity of the platelet outline). The results showed that the platelet boundary is fractal when observed by transmission electron microscopy and that, after an in vitro platelet activation test, the shape of platelets present increased geometric complexity in comparison to the no stimulated platelets (P < 0.001), with 100% correct classification. Computerized fractal analysis of platelet shape by transmission electron microscopy can provide accurate, quantitative, data to study platelet activation. The results may play important roles in the evaluation of the platelets status in pathological conditions, like as atherosclerosis and diabetes mellitus, where in in vivo activated platelets have been described. PMID:25808036

  16. Transcription factors in late megakaryopoiesis and related platelet disorders

    PubMed Central

    Tijssen, M R; Ghevaert, C

    2013-01-01

    Cell type-specific transcription factors regulate the repertoire of genes expressed in a cell and thereby determine its phenotype. The differentiation of megakaryocytes, the platelet progenitors, from hematopoietic stem cells is a well-known process that can be mimicked in culture. However, the efficient formation of platelets in culture remains a challenge. Platelet formation is a complicated process including megakaryocyte maturation, platelet assembly and platelet shedding. We hypothesize that a better understanding of the transcriptional regulation of this process will allow us to influence it such that sufficient numbers of platelets can be produced for clinical applications. After an introduction to gene regulation and platelet formation, this review summarizes the current knowledge of the regulation of platelet formation by the transcription factors EVI1, GATA1, FLI1, NFE2, RUNX1, SRF and its co-factor MKL1, and TAL1. Also covered is how some platelet disorders including myeloproliferative neoplasms, result from disturbances of the transcriptional regulation. These disorders give us invaluable insights into the crucial role these transcription factors play in platelet formation. Finally, there is discussion of how a better understanding of these processes will be needed to allow for efficient production of platelets in vitro. PMID:23311859

  17. Modified expression of surface glyconjugates in stored human platelets

    SciTech Connect

    Dhar, A.; Ganguly, P.

    1987-05-01

    Platelets are anucleated cells which play an important part in blood coagulation and thrombosis. These cells may be stored in the blood bank for only 4/5 days. In order to improve the storage of platelets, it is essential to first understand the changes in these cells due to storage. In this work, human platelets were stored in autologous plasma at 4/sup 0/ or 22/sup 0/ and their surface changes were monitored with three lectins - wheat germ afflutinin (WGA), concanavalin A (Con A) and lentil lectin (LL). Blood was drawn from healthy donors and platelet rich plasma (PRP) was collected by slow speed centrifugation. Platelets stored at either temperature for different times showed increased sensitivity to agglutination by WGA after 34-48 hrs. Lectins, Con A and LL, which were not agglutinating to fresh platelets readily caused agglutination after 48-72 hrs. The platelets stored for 25 hrs or longer period were insensitive to thrombin but showed enhanced aggregation with WGA. Labelling of surface glycoconjugates of stored platelets with /sup 3/H-boro-hydride revealed progressive loss of a glycoprotein of Mr 150,000 (GPIb infinity) together with the appearance of components of Mr 69,000; Mr 60,000; Mr 25,000. New high molecular weight glycoproteins were also detected only in stored platelets. The author studies clearly indicate that modification or altered expression of platelets surface glycoproteins may be one factor of storage related dysfunction of platelets.

  18. Improving platelet transfusion safety: biomedical and technical considerations

    PubMed Central

    Garraud, Olivier; Cognasse, Fabrice; Tissot, Jean-Daniel; Chavarin, Patricia; Laperche, Syria; Morel, Pascal; Lefrère, Jean-Jacques; Pozzetto, Bruno; Lozano, Miguel; Blumberg, Neil; Osselaer, Jean-Claude

    2016-01-01

    Platelet concentrates account for near 10% of all labile blood components but are responsible for more than 25% of the reported adverse events. Besides factors related to patients themselves, who may be particularly at risk of side effects because of their underlying illness, there are aspects of platelet collection and storage that predispose to adverse events. Platelets for transfusion are strongly activated by collection through disposal equipment, which can stress the cells, and by preservation at 22 °C with rotation or rocking, which likewise leads to platelet activation, perhaps more so than storage at 4 °C. Lastly, platelets constitutively possess a very large number of bioactive components that may elicit pro-inflammatory reactions when infused into a patient. This review aims to describe approaches that may be crucial to minimising side effects while optimising safety and quality. We suggest that platelet transfusion is complex, in part because of the complexity of the “material” itself: platelets are highly versatile cells and the transfusion process adds a myriad of variables that present many challenges for preserving basal platelet function and preventing dysfunctional activation of the platelets. The review also presents information showing - after years of exhaustive haemovigilance - that whole blood buffy coat pooled platelet components are extremely safe compared to the gold standard (i.e. apheresis platelet components), both in terms of acquired infections and of immunological/inflammatory hazards. PMID:26674828

  19. 2-Arachidonoylglycerol enhances platelet formation from human megakaryoblasts

    PubMed Central

    Gasperi, Valeria; Avigliano, Luciana; Evangelista, Daniela; Oddi, Sergio; Chiurchiù, Valerio; Lanuti, Mirko; Maccarrone, Mauro; Valeria Catani, Maria

    2014-01-01

    Platelets modulate vascular system integrity, and their loss is critical in haematological pathologies and after chemotherapy. Therefore, identification of molecules enhancing platelet production would be useful to counteract thrombocytopenia. We have previously shown that 2-arachidonoylglycerol (2-AG) acts as a true agonist of platelets, as well as it commits erythroid precursors toward the megakaryocytic lineage. Against this background, we sought to further interrogate the role of 2-AG in megakaryocyte/platelet physiology by investigating terminal differentiation, and subsequent thrombopoiesis. To this end, we used MEG-01 cells, a human megakaryoblastic cell line able to produce in vitro platelet-like particles. 2-AG increased the number of cells showing ruffled surface and enhanced surface expression of specific megakaryocyte/platelet surface antigens, typical hallmarks of terminal megakaryocytic differentiation and platelet production. Changes in cytoskeleton modeling also occurred in differentiated megakaryocytes and blebbing platelets. 2-AG acted by binding to CB1 and CB2 receptors, because specific antagonists reverted its effect. Platelets were split off from megakaryocytes and were functional: they contained the platelet-specific surface markers CD61 and CD49, whose levels increased following stimulation with a natural agonist like collagen. Given the importance of 2-AG for driving megakaryopoiesis and thrombopoiesis, not surprisingly we found that its hydrolytic enzymes were tightly controlled by classical inducers of megakaryocyte differentiation. In conclusion 2-AG, by triggering megakaryocyte maturation and platelet release, may have clinical efficacy to counteract thrombocytopenia-related diseases. PMID:25427281

  20. Current and emerging approaches for evaluating platelet disorders.

    PubMed

    Podda, G; Femia, E A; Cattaneo, M

    2016-05-01

    Platelets play a central role in physiological hemostasis and also in pathological thrombosis. It is well established that congenital or acquired abnormalities of platelet function are associated with a heightened risk of bleeding of variable severity and excessive hemorrhage after surgery or trauma. Several kinds of different platelet function tests have been developed over the years to identify or diagnose platelet function disorders. The use of these tests for the assessment of thrombotic risk or for monitoring the effects of drugs inhibiting platelet function is not well established. Light transmission aggregometry (LTA) is the gold standard for the study of patients with defects of platelet function. Its results are affected by several pre-analytical and analytical variables. The Subcommittee on Platelet Physiology of the Scientific and Standardization Committee of the International Society on Thrombosis and Haemostasis published official guidelines for the standardization of the variables affecting LTA, which should be followed to harmonize the procedures across different laboratories worldwide. The lumi-aggregometer, a modification of LTA that measures platelet secretion in parallel with aggregation, is preferable to LTA for diagnosing inherited defects of platelet function, because it is more sensitive to the most common disorders, which are characterized by abnormalities of platelet secretion. LTA (or lumi-aggregometry) is useful as a first screening test of patients with the clinical suspicion of defects of platelet function, because it helps to provide an interim diagnostic hypothesis, which can then be confirmed or discounted using appropriate and specific tests. PMID:27426860