Uptake Of Colloid Research Articles

Incidental finding of an arteriovenous malformation originating from the diaphragm: Case report and literature review

Arteriovenous malformations (AVMs) are defined as aberrant linkages between arteries and veins in the absence of a capillary network. This case report will discuss the incidental finding of an AVM likely originating from the diaphragm. A 65-year-old female presents for an umbilical hernia repair. Her past medical history is significant for HTN, type 2 diabetes mellitus, gastroesophageal reflux disease, and class 1 obesity. She has a past surgical history of hysteroscopy in 2020 and laparoscopy in 1996. She has no history of tobacco use, alcohol use, or recreational drug use. She is allergic to contrast. A computed tomography (CT) scan was ordered and incidentally showed a soft tissue mass in the left upper quadrant adjacent to the stomach and diaphragm, possibly a gastrointestinal stromal tumor (GIST) or splenule, in addition to diastasis of the abdominal wall. Biopsies of the esophagus, stomach, and duodenum from the esophagogastroduodenoscopy (EGD) were all benign. A nuclear medicine scan of the liver and spleen found an estimated 2.3 cm soft tissue nodule located between the fundus of the stomach and the left hemidiaphragm that does not demonstrate sulfa colloid uptake and is therefore not consistent with a splenule. This is the only incidence cited of an AVM originating from the diaphragm. We suspect that the origin of this AVM is the inferior phrenic artery. The decision for management for this case was to get a CT scan of the abdomen and chest to trace the path of the AVM and manage with surveillance.

Megavoltage radiotherapy effects on organs of the reticuloendothelial system.

To study the uptake capacity of cells from the reticuloendothelial system after irradiation with high-energy X-rays. Eighteen male Wistar rats were distributed in three groups: group A (n = 6): control, unirradiated animals studied alongside animals from group B; group B (n = 6) and group C (n = 6): animals irradiated and studied after 24 and 48 hours, respectively. The rats were anesthetized and placed on a 10 MV linear accelerator. Next, they were irradiated in the abdominal region, with 8 Gy. Twenty-four (groups A and B) and 48 hours later (group C), a colloidal carbon solution (1 mL/kg) was intravenously injected in the tail vein. Fifty minutes later, the spleens and livers were withdrawn and prepared to be studied. Kupffer cells and splenic macrophages containing carbon pigments were counted in an optical microscope. Arithmetic means were calculated for each group and compared among them. X-rays were associated with a reduced number of Kupffer cells containing colloidal carbon, proliferation and enlargement of biliary ducts, hypoplasia, and hepatocyte necrosis. In the irradiated spleen, the colloidal carbon uptake was concentrated in the marginal zone around the white pulp, with an inexpressive uptake of pigments by macrophages from white and red pulps. The X-rays in the rat abdomen are associated with a reduction in the Kupffer cells uptake of colloidal carbon, hepatocyte disorders, bile duct proliferation, and splenic uptake of colloidal carbon concentrated in the marginal zone.

Modelling the bioconcentration of Zn from commercial sunscreens in the marine bivalve Ruditapes philippinarum

Sunscreens contain ZnO particles used as a UV filter cause adverse effects in the marine environment through the release of this metal into seawater and its bioaccumulation in organisms. A mathematical model using sunscreen colloidal residues, seawater and R. philippinarum clams as differentiated compartments, is proposed in order to interpret both the kinetic pattern and the bioaccumulation of Zn in clams. Two kinetic laboratory experiments were conducted, both with and without clams exposed to sunscreen concentrations from 0 to 200 mg L−1. Both the lowest value of uptake rate coefficient obtained when 5 mg L−1 of sunscreen is added (0.00688 L g−1 d−1) and the highest obtained at sunscreen addition of 100 mg L−1 (0.0670 L g−1 d−1), predict a lower bioavailability of Zn in a complex medium such as the seawater-sunscreen mixtures, in comparison to those studied in the literature. The efflux rate coefficient from clams to seawater increased from 0 to 0.162 d−1 with the sunscreen concentrations. The estimated value of the inlet rate coefficient at all studied concentrations indicates that there is a negligible colloidal Zn uptake rate by clams, probably due to the great stability of the organic colloidal residue. An equilibrium shift to higher values of Zn in water is predicted due to the bioconcentration of Zn in clams. The kinetic model proposed with no constant Zn (aq) concentrations may contribute to a more realistic prediction of the bioaccumulation of Zn from sunscreens in clams.

IR780 loaded gelatin-PEG coated gold core silica shell nanorods for cancer-targeted photothermal/photodynamic therapy.

Gold core silica shell (AuMSS) nanorods present excellent physicochemical properties that allow their application as photothermal and drug delivery agents. Herein, AuMSS nanorods were dual-functionalized with Polyethylene glycol methyl ether (PEG-CH3 ) and Gelatin (GEL) to enhance both the colloidal stability and uptake by HeLa cancer cells. Additionally, the AuMSS nanorods were combined for the first time with IR780 (a heptamethine cyanine molecule) and its photothermal and photodynamic capacities were determined. The obtained results reveal that the encapsulation of IR780 (65 µg per AuMSS mg) increases the photothermal conversion efficiency of AuMSS nanorods by 10%, and this enhanced heat generation was maintained even after three irradiation cycles with a NIR (808 nm) laser. Moreover, the IR780-loaded AuMSS/T-PEG-CH3 /T-GEL presented ≈2-times higher uptake in HeLa cells, when compared to the non-coated counterparts, and successfully mediated the light-triggered generation of reactive oxygen species. Overall, the combination of photodynamic and photothermal therapy mediated by IR780-loaded AuMSS/T-PEG-CH3 /T-GEL nanorods effectively promoted the ablation of HeLa cancer cells.

Development of 68Ga-labeled tin colloids for evaluating phagocytic function of Kupffer cells using preclinical PET imaging.

This study aimed to investigate the optimal conditions for producing 68Ga-labeled tin colloid and the feasibility of 68Ga-tin colloid positron emission tomography (PET) for visualization and evaluation of the phagocytic function of Kupffer cells (KCs) in vivo. 68Ga-tin colloid was prepared by adding tin solution (1mM, 0.2mL) to 68Ga solution (1.0mL), followed by pH adjustment with sodium acetate (1M, 0.2mL). Various labeling times were tested to find the optimal one. Colloid size was measured by filtering the solution through three-ply membrane filters (with pore sizes of 200, 3000, and 5000nm), and radioactivity was measured in the whole filtrate and the filters using a gamma counter. The in vitro stability of the colloid was evaluated by the size measurement after incubation under ambient conditions for up to 60min. PET scanning was performed for 30min after intravenous administration of 68Ga-tin colloid solution (4MBq) to healthy rats. Time-activity-curves for the liver, spleen, and blood pool were generated. Finally, liver uptake was compared before and after the establishment of KC-depletion and non-alcoholic steatohepatitis (NASH) rat models. Colloid size increased with increasing labeling time. After pH adjustment, the colloid sizes remained nearly unchanged. The optimal labeling time was determined as 30min. PET imaging of healthy rats revealed that liver uptake of the 68Ga-tin colloid increased with increasing colloid size. In KC-depleted rats, liver uptake significantly decreased (n = 4, p < 0.01). NASH model rats showed significantly decreased uptake of 68Ga-tin colloid in the livers (n = 5, p < 0.01). 68Ga-tin colloid, prepared by a simple radiolabeling method, enabled in vivo PET imaging to evaluate the phagocytic function of KCs.

Triggered Release Enhances the Cytotoxicity of Stable Colloidal Drug Aggregates.

Chemotherapeutics that self-assemble into colloids have limited efficacy above their critical aggregation concentration due to their inability to penetrate intact plasma membranes. Even when colloid uptake is promoted, issues with colloid escape from the endolysosomal pathway persist. By stabilizing acid-responsive lapatinib colloids through coaggregation with fulvestrant, and inclusion of transferrin, we demonstrate colloid internalization by cancer cells, where subsequent lapatinib ionization leads to endosomal leakage and increased cytotoxicity. These results demonstrate a strategy for triggered drug release from stable colloidal aggregates.

A mouse model suggests two mechanisms for thyroid alterations in infantile cystinosis: decreased thyroglobulin synthesis due to endoplasmic reticulum stress/unfolded protein response and impaired lysosomal processing.

Thyroid hormones are released from thyroglobulin (Tg) in lysosomes, which are impaired in infantile/nephropathic cystinosis. Cystinosis is a lysosomal cystine storage disease due to defective cystine exporter, cystinosin. Cystinotic children develop subclinical and then overt hypothyroidism. Why hypothyroidism is the most frequent and earliest endocrine complication of cystinosis is unknown. We here defined early alterations in Ctns(-/-) mice thyroid and identified subcellular and molecular mechanisms. At 9 months, T4 and T3 plasma levels were normal and TSH was moderately increased (∼4-fold). By histology, hyperplasia and hypertrophy of most follicles preceded colloid exhaustion. Increased immunolabeling for thyrocyte proliferation and apoptotic shedding indicated accelerated cell turnover. Electron microscopy revealed endoplasmic reticulum (ER) dilation, apical lamellipodia indicating macropinocytic colloid uptake, and lysosomal cystine crystals. Tg accumulation in dilated ER contrasted with mRNA down-regulation. Increased expression of ER chaperones, glucose-regulated protein of 78 kDa and protein disulfide isomerase, associated with alternative X-box binding protein-1 splicing, revealed unfolded protein response (UPR) activation by ER stress. Decreased Tg mRNA and ER stress suggested reduced Tg synthesis. Coordinated increase of UPR markers, activating transcription factor-4 and C/EBP homologous protein, linked ER stress to apoptosis. Hormonogenic cathepsins were not altered, but lysosome-associated membrane protein-1 immunolabeling disclosed enlarged vesicles containing iodo-Tg and impaired lysosomal fusion. Isopycnic fractionation showed iodo-Tg accumulation in denser lysosomes, suggesting defective lysosomal processing and hormone release. In conclusion, Ctns(-/-) mice showed the following alterations: 1) compensated primary hypothyroidism and accelerated thyrocyte turnover; 2) impaired Tg production linked to ER stress/UPR response; and 3) altered endolysosomal trafficking and iodo-Tg processing. The Ctns(-/-) thyroid is useful to study disease progression and evaluate novel therapies.

Differential hepatic avoidance radiation therapy: Proof of concept in hepatocellular carcinoma patients

PurposeTo evaluate the feasibility of a novel planning concept that differentially redistributes RT dose away from functional liver regions as defined by 99mTc-sulphur colloid (SC) uptake on patient SPECT/CT images. Materials and methodsTen HCC patients with different Child–Turcotte–Pugh scores (A5-B9) underwent SC SPECT/CT scans in treatment position prior to RT that were registered to planning CT scans. Proton pencil beam scanning (PBS) therapy plans were optimized to deliver 37.5–60.0Gy (RBE) over 5–15 fractions using single field uniform dose technique robust to range and setup uncertainty. Photon volumetrically modulated arc therapy (VMAT) plans were optimized to the same prescribed dose and minimum target coverage. For both treatment modalities, differential hepatic avoidance RT (DHART) plans were generated to decrease dose to functional liver volumes (FLV) defined by a range of thresholds relative to maximum SC uptake (43–90%) in the tumor-subtracted liver. Radiation dose was redistributed away from regions of increased SC uptake in each FLV by linearly scaling mean dose objectives during PBS or VMAT optimization. DHART planning feasibility was assessed by a significantly negative Spearman’s rank correlation (RS) between dose difference and SC uptake. Patient, tumor, and treatment planning characteristics were tested for association to DHART planning feasibility using non-parametric Kruskal–Wallis ANOVA. ResultsCompared to conventional plans, DHART plans achieved a 3% FLV dose reduction for every 10% SC uptake increase. DHART planning was feasible in the majority of patients with 60% of patients having RS<−0.5 (p<0.01, range −1.0 to 0.2) and was particularly effective in 30% of patients (RS<−0.9). Mean dose to FLV was reduced by up to 20% in these patients. Only fractionation regimen was associated with DHART planning feasibility: 15 fraction courses were more feasible than 5–6 fraction courses (RS<−0.93 vs. RS>−0.60, p<0.02). ConclusionDifferential avoidance of functional liver regions defined on sulphur colloid SPECT/CT is achievable with either photon VMAT or proton PBS therapy. Further investigation with phantom studies and in a larger cohort of patients may validate the utility of DHART planning for HCC radiotherapy.

Phagocytic function of lower spleen pole and autogenous splenic implants in rats.

To investigate whether there are differences between the phagocytic function of the remaining lower spleen pole after subtotal splenectomy and autogenous splenic implants. Thirty-six male Wistar rats, weighting 364 ± 60g were used. They were subjected to subtotal splenectomy preserving the lower spleen pole and to autogenous splenic implant in the greater omentum. Its viability was assessed microscopically. Phagocytic function was assessed by splenic uptake of the radioisotope-labeled colloid and by macrophages counting. The viability of the autogenous splenic implant and of the lower spleen pole was found in 33 animals, with no difference between them. The weight of the implants was higher than the lower pole of animals from groups G1, G7, G30, G60 and G120. The implants phagocytic function by radioisotope uptake was higher than the lower pole in G7 and G120 groups and it did not differ from the other groups. The number of macrophages was higher in G1, G60, G90 and G120 and did not differ from the other groups. Until the 16th week, the phagocytic function was more pronounced in autogenous splenic implants when compared with the lower spleen pole, but it became similar thereafter.

Liver Sinusoidal Endothelial Cell Transplantation Ameliorated Radiation-induced Liver Deformation And Sulfur Colloid SPECT Defect In Mouse Livers Following Partial Liver Irradiation

Purpose/Objective(s): To examine liver deformation and spatial liver function in a mouse model of radiation induced liver disease (RILD), using functional imaging with 99mTechnetium (99mTc) labeled Sulfur Colloid SPECT/CT. We further investigated whether liver sinusoidal endothelial cell (LSEC) transplantation can improve liver function and ameliorate deformation following image-guided stereotactic partial liver irradiation (HIR). Materials/Methods: DPPIV-deficient or C57Bl6 mice underwent a planning CBCT after gastrograffin gavage. Fifty Gy partial liver irradiation was delivered to the median lobe (ML) using the Small Animal Irradiator Platform (SARRP system) set at 220 kVP and 13.5 mA. Maximum bowel point dose was maintained under 20 Gy to prevent GI toxicity. SPECT/CT imaging was obtained using the Inveon Platform 20 mins after 99mTc Sulfur Colloid injection. Sulfur Colloid uptake was quantified in the irradiated and non-irradiated liver regions using planning CBCT isodose lines. For cell transplantation, DPPIV positive LSECs were isolated from C57Bl/6 mice and then injected intrasplenically to anesthetized congenic DPPIV-deficient mice 24 hours after HIR. The recipient mice were sacrificed 4 months post transplantation. Individual liver lobes were weighted separately and liver tissues were analyzed for engraftment and repopulation of transplanted cells using DPPIV histochemistry. Results: Partial liver irradiation to the ML resulted in a significant decrease in the ML weight from 35 4% of the liver weight to 25 3%, one to two months after irradiation. At 4 months, ML weight reached 16% of the whole liver. Sulfur colloid SPECT/CT imaging demonstrated decreased uptake in the irradiated liver regions by 20-25%, six weeks following HIR. One animal that received HIR, followed by mitotic stimulus with hepatocyte growth factor, showed virtually no uptake in the irradiated lobe with significant compensatory hypertrophy of the unirradiated liver one year after HIR. LSEC transplantation restored ML liver weight and by 4 months made up 37-40% of the liver weight while also restoring 99mTc sulfur colloid uptake in the irradiated lobe to baseline levels. DPPIV histochemistry confirmed near total replacement of the irradiated LSECs by the transplanted DPPIV positive cells. Conclusions: This data suggests that HIR resulted in a time-dependent decrease in the weight and functional uptake of 99mTc labeled sulfur colloid in the irradiated liver lobe. LSEC transplantation restored liver weight and improved liver function as demonstrated by 99mTc sulfur colloid SPECT/ CT imaging. Our data provide a rationale for investigating the use of 99mTc sulfur colloid SPECT/CT imaging to monitor patients at risk for developing RILD and LSEC transplantation to ameliorate against RILD. Author Disclosure: R. Kabarriti: None. H. Yaffe: None. W. Zhang: None. W.P. Koba: None. L. Liu: None. P. Asp: None. W.A. Tome: None. C. Guha: None.

Focal Fat Sparing of the Liver

Fat spared area of liver can appear as focal areas of elevated FDG uptake on a PET scan. This may mimic metastases. PET scan performed for metastatic workup in a 35-year-old female patient, a case of exocrine tumor of the pancreas, showed focal areas of increased FDG uptake. Contrast-enhanced CT performed as a part of the PET/CT study showed enlarged fatty liver with focal hyperdense areas suggesting fat sparing. Sulfur colloid scan showed physiological colloid uptake in the suspicious areas indicating preserved Kupffer cell function. The patient is on close follow-up without any evidence of metastatic disease.

90Y-labeled antimony trisulfide colloid as promising therapeutic agent: Physicochemical characterization and biological evaluation

Introduction The suitability of 90Y-labeled antimony trisulfide colloid (ATC) for the preparation of therapeutic radiopharmaceutical was studied taking into accounts its physicochemical properties and biological behavior in rats. Material and methods The labeling efficiency of 90Y- and 99mTc-labeled colloid particles was investigated by ITLC-SG and paper chromatography, the in vitro stability of the colloid was tested in human serum, while in vivo experiments were performed on healthy Wistar rats. Analysis of the particles enclosed the size (TEM), determination of the zeta potential (Zetasizer Nano) as well as radioactivity particle size distribution (filtration analysis). Results 90Y-labeled ATC can be prepared in high yield under investigated conditions Labeling efficiency was >95% and filtration analysis showed that more than 90% of radioactive particles were smaller than 20 nm. The particles with the size range of 6-22 nm were achieved by using polyvinyipyrrolidone (mol wt ~44,000). The 90Y-ATC was quite stable in vitro in human serum. Tissue distribution studies in rats confirmed that the liver and spleen uptake of 90Y-labeled colloid was three-fold lower in comparison with 99mTc-ATC, although the bone uptake was five-fold higher at 20 min post injection. Conclusions 90Y-labeled ATC showed high labeling efficiency and good stability, and might be well suited for therapeutic application in nuclear medicine.

8:08 AM Abstract No. 60 - Fusion MAA-sulfur colloid spect imaging for Yttrium-90 radioembolization: towards customized physiology-based dose planning

Purpose Yttrium-90 (90Y) radioembolization dose planning requires balancing caution against toxicity with aggressiveness for efficacy, but each is impossible to predict based solely on morphologic imaging. We investigate the use of fusion MAA-sulfur colloid SPECT imaging to provide physiologic information relevant to dose calculation and outcomes. Materials and Methods A dual SPECT protocol was used with IA injection of technetium-99m (99mTc)-MAA (1 mCi) as a predictor of subsequent 90Y distribution, followed by IV 99mTc-sulfur colloid (5 mCi) as a biomarker for normal hepatic tissue. The SPECT data were co-registered and fused. A voxel based method was used to predict the 90Y radiation absorbed dose to functional hepatic tissue by calculation of 99mTc-MAA activity in voxels with 99mTc-sulfur colloid uptake. Similarly, the absorbed dose to tumor was predicted by calculation of 99mTc-MAA activity in voxels without 99mTc-sulfur colloid. Response (mRECIST) was recorded at 3 months, laboratory data were collected at 2, 4 and 8 weeks, and patients were followed until death. Retrospective SPECT based dosimetry was correlated with parameters of toxicity and efficacy and compared with standard parameters of dosimetry, administered activity, and whole liver absorbed dose. Results A total of 56 patients were included (32 M, 24 F; median age 62; 27 HCC, 29 CRC, 32 resin, 24 glass microspheres, median activity 2.02 GBq, median whole liver dose 70 Gray). Toxicity parameters (serum bilirubin, AST, ALT, albumin, hemoglobin, and platelets) correlated significantly with SPECT-based functional liver absorbed dose (median 38 Gy, p Conclusion Fusion MAA-Sulfur colloid SPECT is useful to predict tumor and functional liver absorbed dose, which correlate with efficacy and toxicity, and may be used in the future to develop an individualized physiology-based dose-planning method.

Effect of rosemary (Rosmarinus officinalis) extract on the biodistribution of 99mTc sulphur colloid and on the radiolabeled blood constituents

With this study we evaluated the effects of the herb rosemary (Rosmarinus officinalis L. Lamiaceae) extract on the labeling of blood constituents with technetium- 99m (99mTc) labeled sulphur colloid and on the biodistribution of 99mTc-Sulphur Colloid in Wistar albino rats. For this purpose, two groups of animals (male wistar rats, 130–140g) were treated (1mL) with a rosemary extract (750mg/kg body wt.,n=9) and water (control, n=9) separately by gavage for five days. 99mTc-Sulphur Colloid was administrated by intravenous injection; organs/tissues were withdrawn and weighted. Blood was centrifuged, plasma and blood cells were isolated. The radioactivity was counted to calculate the percentage of activity per gram for each organ/tissue and percentage of activity in blood cells and plasma. A signii cant increase (p<0.05) in the uptake of 99mTc-Sulphur Colloid in the liver after the treatment with rosemary extract was observed. These results indicate that the substances or metabolites of the rosemary extract would change the biodistribution of 99mTc-Sulphur Colloid.

Outcomes of Stereotactic Radiation Therapy (SRT) for Primary and Metastatic Liver Tumors with 3-D CT and Single Photon Emission Computed Tomography (3D-CT/SPECT) Treatment Planning

SPECT provides functional imaging of the liver parenchyma through the uptake of radioactive colloid by Kupffer cells in proportion to vascular perfusion. We report on outcomes and toxicity of liver SRT/SBRT based on 3D-CT/SPECT treatment planning with conformal avoidance of well-perfused functional normal liver volumes (FNLV).

Influence of Hemoglobin Level on Clinical Findings In Infants with Sickle Cell Anemia: Data From BABY HUG

AbstractAbstract 1631 Introduction:Infants with sickle cell anemia (SCA) are at risk for organ damage and clinical events. Risk may vary depending on steady state hemoglobin level. BABY HUG (ClinicalTrials.org, NCT00006400), a NHLBI-NICHD supported phase III randomized placebo-controlled trial, examined the ability of hydroxyurea (HU) to reduce end organ damage to the kidneys and spleen and attenuate other complications of SCA in infants. In this secondary study, we investigated whether placebo-treated subgroups defined by extremes of baseline hemoglobin level differed from one another in frequency of sickle cell-related complications and other laboratory findings, and then compared these data to the entire group of infants treated with HU. Methods:BABY HUG subjects randomized at ages 9 – 18 mo were treated with hydroxyurea (20 mg/kg/d) (N=96) or with placebo (N=97) for 2 years. Those randomized to placebo were classified according to their age-adjusted baseline hemoglobin level and subgroups in the lowest (n=24) and highest (n=24) quartiles compared. (Demarcating Hb values were: age 9 to <12 mo, <8.0 vs. >10.2gm/dL; age12 – 18 mo, <8.1 vs. >9.9gm/dL.) Results:BABY HUG primary endpoints of spleen (splenic uptake of 99mTc sulfur colloid on liver-spleen scan) and kidney (GFR by DTPA clearance) function did not differ in placebo group subjects who were in the lowest and highest quartile hemoglobin levels. However, those in the lowest hemoglobin quartile had a higher incidence of acute chest syndrome (ACS) than those in the highest quartile (0.31 vs. 0.02 events/person-year, RR 14.4, p=0.01) and this difference was significantly attenuated by HU (0.05 events/person-year). The relative risk for developing a pain crisis did not differ between the two placebo subgroups (2.2 vs. 2.1 events/person-year), but HU significantly reduced pain frequency compared to either subgroup (0.94 events/person-year, p<0.001). Subjects in the lowest hemoglobin quartile had higher baseline mean TCD velocities than those in the highest quartile (126.2 vs. 112.4 cm/sec, p=0.008). These differences persisted over the two-year period of study, with exit values of 164.9 and 139.6 cm/sec, respectively (p=0.003). By comparison mean TCD velocity in the HU-treated group was 124.5 cm/sec at baseline and 145.6 at exit. Results of neurocognitive testing were not statistically different between groups; however, a trend toward a lower performance developmental index (PDI, p=0.07), but not a lower mental development index (MDI, p=0.15), was observed in subjects with the lowest hemoglobin levels. Subjects in the lowest quartile also had a higher mean WBC (18.0 vs. 11.4 × 109/L, p<0.001), absolute neutrophil count (5.3 vs. 3.6 × 109/L, p=0.001), and platelet count (416 vs. 315 × 109/L, p=0.0001) compared to those with the highest hemoglobin. The laboratory findings of patients receiving HU also were significantly lower than those of subjects in the lowest hemoglobin group and similar to those in the highest hemoglobin group. Conclusions:Severe anemia in very young patients with SCA was associated with elevated WBC and platelet counts and higher TCD velocities. Interestingly, severe anemia also was associated with increased frequency of ACS, in contrast to the association of ACS with higher hemoglobin levels in older patients. Future studies will need to confirm this relationship and clarify to what extent associated findings (e.g., hyposplenia, elevated WBC or platelet count) contribute to this susceptibility. Severe anemia in young SCA patients is a negative prognostic factor that is significantly impacted by early hydroxyurea therapy. Disclosures:Off Label Use: Hydroxyurea is not approved by FDA for infants with sickle cell disease. Miller:NIH/NHLBI; Emmaus Med Inc, Novartis Pharmaceutical; St Jude Childrens Hospital: Research Funding.

The effect of applied cytotoxic drugs on biological behaviour of 99mTc-radiopharmaceuticals

This study was aimed at investigating the influence of certain cytotoxic drugs on the organ uptake of the following 9mTc-radiopharmaceuticals: 99mTc-2,3-dicarboxypropane-1, 1-diphosphonic acid, 99mTc-meso-2,3-dimercaptosuccinic acid, 9mTc-tin colloid and 99mTc-macraggregated albumin. Methotrexate sodium and cyclophosphamide were used as models to evaluate these effects. Two groups of healthy male Wistar rats were treated separately by oral application of the drugs for 7 days. On the eighth day, each of the 99Tc-radiopharmaceuticals was applied in a separate group of treated animals. They were sacrificed at different time intervals and the radioactivity in the organs of interest was measured. The organ uptake of the 99mTc-radiopharmaceuticals in an additional control group of animals was also studied. The results obtained showed an alteration in the organ uptake of 99mTc-radiopharmaceuticals in animals treated with cytotoxic drugs. In the rats treated with methotrexate sodium, there was a higher uptake of 99mTc-meso-2,3-dimercaptosuccinic acid in the bones, stomach and intestine, a higher uptake of 99mTc-2,3-dicarboxypropane-1-,1-diphosphronic acid in the bones, intestine, blood and muscle, a lower uptake of 99mTc-tin colloid in the liver and a lower accumulation of 99mTc-macroaggregated albumin in the lungs. Cyclophosphamide-treated animals showed enhanced uptake of 99mTc-meso-2,3-dimercaptosuccinic acid in the kidneys, a twofold enhanced uptake of 99mTc-2,3-dicarboxypropane-1,1-diphosphronic acid in all organs except the stomach, a decreased uptake of 99mTc-tin colloid in the lungs, spleen and kidneys and a significantly decreased uptake of 99mTc-macroaggregated albumin in the lungs. These results confirm that both methotrexate sodium and cyclophosphamide may alter the organ uptake of 99mTc-radiopharmaceuticals in experimental animals.

Activity of pulmonary intravascular macrophages in cats and dogs with and without adult Dirofilaria immitis

Pulmonary intravascular macrophages (PIMs), large (20–80 μm diameter) monocytes are present in sheep, pigs, and horses, but not in dogs, rats, rabbits, or primates. The present study evaluated the phagocytic activity of various organs in cats and dogs and determined the influence of Dirofilaria immitis infections on PIM activity. Live or dead adult heartworm (HW) was transplanted via jugular venotomy into cats and dogs. Cats (four per group) were allocated to five groups: surgical controls—no HW, dead HW for 1 week, live HW for 1 week, dead HW for 3 weeks, or live HW for 3 weeks. Radioactive technetium (Tc-99m, 1.2 mCi in 0.3 ml) sulfa-colloid was injected intravenously. All cats with HW were clinically asymptomatic and developed radiographic pulmonary parenchymal changes. No gross changes were visible at necropsy for cats with HW; inflammatory changes were less severe in cats with live HW. In cats with dead HW for 3 weeks, worms were present but folded, flattened, and located in distal pulmonary arteries. Uninfected control dogs and those with dead HW did not demonstrate any PIM activity. In control cats, lungs were the primary phagocytic organ after systemic IV colloid injection (72.5% of the total recovered radioactive dose). The lung and liver together represented over 95% of the recovered Tc-99m colloid in all cats. In each group of cats with HW, phagocytic activity of the lung was significantly less ( p < 0.001) than the PIM activity of controls. Cats with dead HW at 1 week (50.1%) had a significant ( p < 0.019) decrease in PIM activity compared with cats with dead HW at 3 weeks (59.5%). The PIM activity in cats with live HW was significantly decreased ( p < 0.001) from that in groups with dead HW, but there was no significant difference between the two groups infected with live worms. There were no significant differences in recovery between any groups in pairwise analysis of the spleen, heart, skeletal muscle, kidney, bone marrow, or blood. Significant increases ( p < 0.001) in liver activity for each group inversely reflected the decreased lung activity; consistent with increased hepatic uptake of Tc colloid “escaping” a relatively suppressed lung macrophage system. Transmission electron microscopy confirmed PIM glycocalyx changes and vacuolization, moderate Type 1 cell damage and Type II cell hypertrophy in cats with dead HW. There was no evidence of PIM death. The significant decrease in PIM activity in groups with dead HW and a greater decrease in groups with live HW are consistent with a down-regulation of PIM function in cats with live HW.

Quantitative intracellular magnetic nanoparticle uptake measured by live cell magnetophoresis

Superparamagnetic iron oxide (SPIO) particles have been used successfully as an intracellular contrast agent for nuclear MRI cell tracking in vivo. We present a method of detecting intracellular SPIO colloid uptake in live cells using cell magnetophoresis, with potential applications in measuring intracellular MRI contrast uptake. The method was evaluated by measuring shifts in mean and distribution of the cell magnetophoretic mobility, and the concomitant changes in population frequency of the magnetically positive cells when compared to the unmanipulated negative control. Seven different transfection agent (TA) -SPIO complexes based on dendrimer, lipid, and polyethylenimine compounds were used as test standards, in combination with 3 different cell types: mesenchymal stem cells, cardiac fibroblasts, and cultured KG-1a hematopoietic stem cells. Transfectol (TRA) -SPIO incubation resulted in the highest frequency of magnetically positive cells (>90%), and Fugene 6 (FUG) -SPIO incubation the lowest, below that when using SPIO alone. A highly regular process of cell magnetophoresis was amenable to intracellular iron mass calculations. The results were consistent in all the cell types studied and with other reports. The cell magnetophoresis depends on the presence of high-spin iron species and is therefore expected to be directly related to the cell MRI contrast level.

In whole blood, LPS, TNF-alpha and GM-CSF increase monocyte uptake of 99mtechnetium stannous colloid but do not affect neutrophil uptake

(99m)Technetium stannous colloid (TcSnC) is used in white cell scanning. It labels neutrophils and monocytes via phagocytosis, with uptake mediated by the phagocytic receptor CD11b/CD18 in neutrophils. Uptake of TcSnC is altered by gram-negative infection, possibly due to the endotoxin component lipopolysaccharide (LPS) or to cytokines released during infection (e.g., TNF-alpha and IFN-gamma). Endotoxemia and increased TNF-alpha levels also occur in inflammatory bowel disease. Another potential confounder in cell labeling is that sepsis patients may be treated with GM-CSF and G-CSF, which alter phagocytic cell function. This study aimed to determine how these factors affect TcSnC cellular uptake. Whole blood from six healthy volunteers was incubated with LPS, TNF-alpha, IFN-gamma, GM-CSF or G-CSF. Samples were then mixed with TcSnC. Blood was separated across density gradients and imaged using a gamma camera. Three radioactive count peaks were observed in each tube: free plasma activity, mononuclear cell uptake and neutrophil uptake. Compared with controls, significant increases in mononuclear cell uptake were induced by LPS, TNF-alpha and GM-CSF stimulation. It was incidentally noted that exogenous estrogens appear to affect TcSnC labeling and may influence the neutrophil response to stimulation. Neutrophil uptake and plasma activity were not significantly affected. IFN-gamma and G-CSF had no significant effect. In whole blood, the effect of LPS on TcSnC monocyte uptake is different to its effect on neutrophils, consistent with previously reported differences in CD11b/CD18 expression. TNF-alpha response parallels LPS response. GM-CSF also increases TcSnC uptake by monocytes. These effects should be considered when using TcSnC for imaging purposes, as they will tend to increase monocyte labeling. Estrogens may also affect TcSnC labeling. Responses to IFN-gamma and G-CSF are consistent with previously reported effects of these cytokines on CD11b/CD18 expression.