Miklos Fogarasi - Academia.edu (original) (raw)
Papers by Miklos Fogarasi
Clinical Colorectal Cancer, Aug 1, 2001
PubMed, 1994
Recently, a method for the direct labeling of antibodies with 99mTc was described in which sulfhy... more Recently, a method for the direct labeling of antibodies with 99mTc was described in which sulfhydryls were reportedly generated by reduction of antibody disulfides with ascorbic acid. Thereafter, these proteins may be labeled at high efficiency with 99mTc following reduction of pertechnetate with dithionite. This investigation was initially conducted to evaluate the mechanism of the increased stability towards cysteine challenge reported for the label and subsequently to determine the role of ascorbate in the labeling process. Methods: It was possible to reproduce the reported high labeling efficiencies by increasing the dithionite concentration fivefold, presumably because of variabilities among lots of commercial sodium dithionite. Results: Despite success in labeling, it was not possible to confirm that antibody reduction followed the treatment with ascorbate. Using both Ellman's reagent and 2,2' dithiodipyridine as indicators, we were unable to detect sulfhydryls on one IgG antibody treated at ten times the suggested ascorbate-to-antibody molar ratio. It was estimated that the number of sulfhydryls generated could not have been more than 1% (dithiodipyridine) to 2% (Ellman's). Furthermore, radiolabeling efficiencies for two IgG antibodies and stabilities of the label to cysteine challenge were unchanged when the ascorbate was eliminated. The number of sulfhydryls generated by treatment of the antibody with dithionite at 1-2 times the concentration required for adequate labeling was about 1% (dithiodipyridine) to 5% (Ellman's). Conclusion: For the conditions of this investigation and for the antibodies employed, ascorbate apparently played no more than a minor role at best in the labeling process. If antibody reduction occurred, this most likely was a result of residual dithionite presented to the protein along with the reduced 99mTc.
PubMed, Jun 1, 1996
Methods for labeling antibodies with 99mTc cannot be used without modification for radiorhenium d... more Methods for labeling antibodies with 99mTc cannot be used without modification for radiorhenium despite the similar chemistries, in part because of a lower redox potential of rhenium and therefore a greater tendency to reoxidize. We have investigated conditions for directly labeling B72.3 IgG with 188Re via both mercaptoethanol and stannous ion antibody reduction. The reduced 188Re was stabilized for transchelation as the glucoheptonate complex and transchelated in the presence of excess stannous ion. End points were low "non-specific" binding (i.e. labeling in the absence of antibody reduction) and increased stability to cysteine challenge. By both methods, labeling efficiencies after about 15 minutes averaged 58.77% with as little as 4% non-specific binding. Specific activities of 15 muCi/microgram was achieved after 1.5 hours. By investigating labeling condition, it was possible to improve the stability of the label on stannous ion reduced antibody such that the in vitro and in vivo properties of 188Re were largely independent of labeling method. For example, losses of 188Re due to oxidation (16%) and to cysteine (7%) during 37 degrees C serum incubations for 24 hours were identical for both methods. Furthermore, after the administration to normal mice, whole body clearance and the accumulations of 188Re at 2.5 and 24 hours in blood and in most organs were also independent of labeling method. In conclusion, two different direct labeling methods provided a 188Re-labeled antibody with identical stabilities and with in vivo properties not greatly different from that seen for the same antibody radiolabeled directly with 99mTc.
PubMed, 1996
Oligonucleotides, particularly single stranded, may ultimately be of considerable use as radiopha... more Oligonucleotides, particularly single stranded, may ultimately be of considerable use as radiopharmaceuticals. We have compared a synthetic 22-base single-stranded phosphodiester DNA with its phosphorothioate analog after both were radiolabeled with 99mTc via the hydrazino nicotinamide chelator. Whole body clearance of the label in mice was much slower when introduced on the phosphorothioate (30% vs. 75% clearance at 6 hr) because of immediate and persistent accumulation in liver (47% vs. 2% injected dose/g at 4 hr). The label in both cases was present in urine primarily on low molecular weight catabolites. High-performance liquid chromatography analysis of 37 degrees C serum incubates showed serum protein binding of 99mTc in both cases (about 100% bound at 24 hr) but to different proteins. Different behavior with respect to protein binding was also observed in the analysis of liver and kidney homogenates: the phosphodiester label was almost quantitatively converted to lower molecular weight catabolites after only 15 min, whereas the phosphorothioate label was primarily on proteins. The rapid digestion of the phosphodiester by nucleases was not observed, probably because protein binding of the labeled oligonucleotides stabilized against degradation. Thus the phosphodiester DNA may be the preferred 99mTc-labeled oligonucleotide in certain circumstances to avoid the high and persistent liver uptake observed with the phosphorothioate DNA.
PubMed, Dec 1, 1995
Single-stranded RNA and DNA oligonucleotides may be useful as radiopharmaceuticals for antisense ... more Single-stranded RNA and DNA oligonucleotides may be useful as radiopharmaceuticals for antisense and other in vivo applications if convenient methods for stably attaching radionuclides such as 99mTc can be developed. Methods: To radiolabel DNA with 99mTc, we have used the hydrazino nicotinamide (SHNH) moiety developed elsewhere. The diethylenetriaminepentacetic acid (DTPA) chelate was used to label DNA with 111In for comparison. Complementary 22-base, single-stranded oligonucleotides were obtained, each with a primary amine attached to either 3' or 5' end with a biotin moiety on the opposite end. The DNA was conjugated with SHNH by a N-hydroxysuccinimide derivative with DTPA by the cyclic anhydride. Results: Reversed-phase HPLC analysis showed that essentially complete conjugation was achieved in both cases. The purified SHNH-DNA was radiolabeled with 99mTc by transchelation from glucoheptonate at labeling efficiencies of up to 60% and DTPA-DNA with 111In acetate at up to 100% efficiency. After labeling, the ability of the DNAs to bind to streptavidin through the biotin moieties and to hybridize with their complementary DNA in saline was retained for both radiolabels as determined by size-exclusion HPLC analysis. HPLC radiochromatograms of serum incubates showed a shift to 99mTc, but not 111In, to a high molecular weight, strongly suggesting serum protein binding in the former case only. Low-molecular weight degradation products were seen with 111In, but not with 99mTc and may be related to the use of phosphodiester-linked oligonucleotides. As a further measure of label stability, the DNAS were bound to streptavidin-conjugated magnetic beads and incubated in fresh 37 degrees C human serum. Less than 4% of 99mTc and 14% of 111In was lost in 24 hr. Conclusion: Amino-modified, single-stranded DNA can be stably radiolabeled with 99mTc by the SHNH moiety without loss of function.
PubMed, 1993
To investigate the in vivo and in vitro properties of 99mTc when labeled to antibodies via one di... more To investigate the in vivo and in vitro properties of 99mTc when labeled to antibodies via one direct and one indirect method, the B72.3 and C110 IgG antibodies were radiolabeled directly via stannous ion reduction and indirectly via the hydrazino nicotinamide chelator and compared in vitro and in vivo. Antibody avidity (but not immunoreactive fraction) appeared to be independent of labeling methods for both antibodies. Following stannous ion reduction, antibodies were fragmented by denaturing SDS PAGE although only slight evidence of fragmentation was found in vivo. The direct label was instable to transchelation to cysteine and glutathione in vitro and in vivo. Following intravenous administration, urinary excretion of activity was threefold greater for the direct label and was almost exclusively labeled cysteine and glutathione. Significant differences in the biodistribution of 99mTc were also observed: liver levels were lower, kidney levels were higher and clearance of label from blood and tissues was faster for the direct label. At Day 1, tumor accumulation was threefold lower for the direct label although most normal tissues were also lower. In conclusion, when labeled to two antibodies by one direct method, 99mTc is unstable towards transchelation relative to one indirect method. These relative instabilities greatly influenced the biodistributions in mice and may influence the quality of images obtained in patients.
Journal of Clinical Oncology, Jun 1, 2023
Journal of Immunotherapy, Aug 1, 1994
Nuclear Medicine and Biology, Nov 1, 1994
Recent investigations have shown that transchelation to cysteine is a principal mode of in viva i... more Recent investigations have shown that transchelation to cysteine is a principal mode of in viva instability of *"Tc-labeled antibodies. In this investigation, a cysteine challenge assay was used to measure the in vitro instability of *Tc directly labeled to two IgG antibodies (B72.3 and Cl 10) via two established direct labeling methods employing mercaptoethanol and stannous ion for antibody reduction and by a novel method using glutathione for this purpose. For both antibodies, the greatest instability to cysteine occurred with stannous ion reduction. The stability of glutathione-reduced B72.3 was indistinguishable from mercaptoethanol-reduced B72.3 whereas glutathione-reduced Cl 10 showed stability roughly intermediate between that of the other reducing agents for this antibody. Results obtained in normal mice were in the direction predicted by the assay: for both antibodies, urinary clearance of %Tc was fastest in mice receiving antibodies labeled via stannous ion reduction, presumably because of the increased transchelation of label to cysteine in uivo. Urinary clearance was slower and identical in mice receiving B72.3 labeled via glutathione or mercaptoethanol whereas clearance in the case of glutathione-reduced Cl10 was intermediate between that of the other two reducing agents. At both time points, higher radioactivity levels were observed in kidneys and lower levels in blood and most other tissues for both antibodies in the case of stannous ion reduction as expected for the label of greatest instability. In the B72.3 case, with only one exception, tissue and blood levels following administration of glutathione-reduced antibody were indistinguishable from that following administration of mercaptoethanol-reduced antibody. In the Cl 10 case, significant differences in activity levels were observed in several tissues between glutathione-and mercaptoethanol-reduced antibodies. In conclusion, the relative in vivo behaviour of %'"Tc when administered to mice while labeled to two IgG antibodies were successfully predicted based on the results of an in vitro cysteine challenge assay.
Annals of Emergency Medicine, 2021
Nuclear Medicine Communications, 1995
Bioconjugate Chemistry, 1995
Consideration is now being given to the use of avidin (or streptavidin) and biotin for radiothera... more Consideration is now being given to the use of avidin (or streptavidin) and biotin for radiotherapy of tumor. Accordingly, the goal of this study was to radiolabel a mouse metallothionein-streptavidin fusion protein with 188Re and to compare its properties to those of the same fusion protein radiolabeled with 99mTc. A recombinant metallothionein-streptavidin fusion protein was radiolabeled by transchelation with 99mTc- and 188Re-glucoheptonate. Labeling efficiency, which was not optimized for either radionuclide, was approximately 60% for 99mTc and 20% for 188Re. Radiochemical purity was demonstrated by size exclusion HPLC both by nearly quantitative shifts of the 188Re label to higher molecular weight upon the addition of biotinylated antibody and by the absence of a shift with biotinsaturated 188Re-metallothionein-streptavidin. Stability of the labels in 37 degrees C serum was evaluated by comparing the HPLC radiochromatograms of serum samples both before and after the addition of biotinylated antibody. The 188Re label behaved like 99mTc in that the same peaks were evident, including one prominent peak due to labeled cysteine. Recoveries during HPLC analysis of serum samples showed that oxidation rates to perrhenate and pertechnetate were identical. However, instability to cysteine challenge was greater for 188Re; for example, the loss of label to cysteine after 24 h under one set of conditions was 41% for 188Re and 22% with 99mTc. Analysis by HPLC of liver and kidney homogenates from mice administered the labeled antibodies were qualitatively and, in large measure, quantitatively independent of label. Biodistributions at 5 h in normal mice were statistically identical between the two labels in blood and in most tissues. In conclusion, streptavidin may be radiolabeled with radiorhenium using recombinant mouse metallothionein as a bifunctional chelator, and under one set of labeling conditions at least, 188Re showed similar in vitro and in vivo behavior to that of 99mTc labeled to the same fusion protein.
Orvosi hetilap, Jan 18, 1994
The authors summarize the recent findings obtained in the field of inflammatory cytokines with pa... more The authors summarize the recent findings obtained in the field of inflammatory cytokines with particular attention on interleukin-6 (IL-6). After a short review of the molecular biology and of the cellular effects of IL-6, the most important clinical relations of IL-6 in hepatic diseases, in non-specific inflammatory bowel diseases (Crohn's disease and ulcerative colitis) and in certain autoimmune diseases are provided. The simultaneous discussion of molecular and clinical data contribute to the understanding of pathomechanisms.
Journal of nuclear medicine : official publication, Society of Nuclear Medicine, 1996
Animal studies of infection imaging by a two-step protocol have shown that important improvements... more Animal studies of infection imaging by a two-step protocol have shown that important improvements in target to nontarget ratios are possible. In this protocol, unlabeled streptavidin is administered and allowed sufficient time to accumulate in the lesion, probably by nonspecific processes, and to clear elsewhere. Thereafter, 111Inbiotin is administered. A fraction of the labeled biotin may be retained in the lesion because of biotin's high affinity for streptavidin while most of the activity is cleared through the kidneys. Radioscintigraphy with unlabeled streptavidin followed with 111Inlabeled biotin was performed in 15 patients with chronic osteomyelitis. As controls, each patients received either 111In-labeled biotin without the preadministration of streptavidin or 111In-labeled nonspecific IgG. Regions of focal uptake were identified in all patients receiving streptavidin followed by radiolabeled biotin as early as 10 min postadministration of radioactivity, and retention of...
Education Sciences
Sound foundational knowledge improves disease conceptualization and clinical diagnosis. Vertical ... more Sound foundational knowledge improves disease conceptualization and clinical diagnosis. Vertical integration (VI) is an appealing educational strategy to refresh relevant pre-clinical information during clinical rotations. However, an optimal learning approach for this has not yet been established. We hypothesized that a small group collaborative discussion format might serve as an appealing learning method to deliver integrated material and increase retention. During AYs 2018/2019 and 2019/2020, our multidisciplinary team utilized a Colorectal Cancer workshop incorporating pre-clinical material for Y3 students on Surgical Clerkship. In search of an optimized way to deliver vertically integrated content, we alternately presented the workshop material either in a small group (SG) case-based collaborative format or as a standard-sized group (StdG) exercise. We achieved this by testing immediate and late (4-week post-event) recall and assessing student satisfaction with the VI strategy...
Journal of Leukocyte Biology
ABSTRACT
PLOS ONE, 2022
Background and objectives Human trafficking is a significant problem in which healthcare workers ... more Background and objectives Human trafficking is a significant problem in which healthcare workers are in a unique position to intervene. This study sought to determine the self-reported knowledge levels of healthcare providers most likely to come in direct contact with victims of human trafficking. Methods An anonymous survey assessing self-reported knowledge of human trafficking was developed and distributed online. Demographic information and questions pertaining to training and knowledge of trafficking in a healthcare setting were asked. The primary outcomes were descriptive statistics and secondary outcomes were comparisons among demographic groups. Qualitative methodology via content analysis was implemented on an open-ended question. Results The 6,603 respondents represented all regions of the country. Medical, nursing, and physician assistant students comprised 23% of the sample, while 40% were either physicians, fellows, or residents. Less than half the respondents (42%) have...
Journal of Leukocyte Biology, 1992
To test our hypothesis that monocytes (M phi) and their mediators are major contributors to ethan... more To test our hypothesis that monocytes (M phi) and their mediators are major contributors to ethanol-related immunodepression, the modulating capacity of acute ethanol treatment was assessed on the production of transforming growth factor-beta (TGF beta) and prostaglandin E2 (PGE2) by human peripheral blood M phi. We demonstrate that acute in vitro treatment of adherent M phi with either 50 or 150 mM ethanol induced a significant increase in the production of TGF beta (P < 0.045 and P < 0.001, respectively). Furthermore, M phi pretreatment with both 50 and 150 mM ethanol augmented TGF beta production in response to subsequent stimulation with the synthetic bacterial analog, muramyl dipeptide (MDP) (P < 0.05 and P < 0.001, respectively). Ethanol also increased TGF beta production in interferon gamma (IFN gamma-activated M phi in response to MDP stimulus (P < 0.05). M phi TGF beta levels, however, were always lower in IFN gamma-activated than in non-IFN gamma-activated M phi after the same stimulation with ethanol plus MDP, suggesting that M phi preactivation by IFN gamma can partially counteract the TGF beta inducing potential of ethanol. Similar to its TGF beta-inducing potential, ethanol (150 mM) had the capacity to induce PGE2 production in adherent human M phi (P < 0.045). However, ethanol failed to augment M phi PGE2 production induced by the PGE2 secretagogue, MDP. TGF beta induction by ethanol was unaffected by the presence of cyclooxygenase inhibitor, suggesting that ethanol-induced M phi TGF beta production does not require M phi PGE2 production. These results indicate that ethanol is a potent inducer for inhibitory M phi mediators, TGF beta and PGE2, and also has the capacity to augment M phi TGF beta production in response to subsequent stimulation. Thus, ethanol-induced elevation of M phi TGF beta and PGE2 production might contribute to decreased T cell proliferation and abnormal M phi functions after alcohol exposure, resulting in a depressed immune response.
Cureus, Jan 22, 2018
Longevity in cancer patients with brain metastases is increasingly being observed. This raises di... more Longevity in cancer patients with brain metastases is increasingly being observed. This raises discussions about how best to maintain a good quality of life for these patients. Recent data suggest that post-treatment quality of life (QoL) can be maintained using new treatment options, but little data exist regarding the QoL in long-term survivors. This study of 19 patients surviving greater than two years from the initial treatment of brain metastases suggests that long-term QoL can be better than at the start of treatment and perhaps even better than normal, especially between three and five years post-treatment. This improved QoL seems mostly attributable to improved functional and social well-being and is possible as long as emotional and physical well-being are maintained within the normal range.
Journal of Clinical Oncology, 2017
15 Background: Responding to calls for education in Cancer Survivorship, the Frank H. Netter MD S... more 15 Background: Responding to calls for education in Cancer Survivorship, the Frank H. Netter MD School of Medicine introduced new content using an interactive student elective for Y2 medical students with the goal of improving medical knowledge and confidence in caring for survivors. Methods: Learning objectives and course content were developed based upon the ASCO curriculum (ASCO Core Curriculum for Cancer Survivorship Education Shapiro, CL et al, Journal of Oncology Practice Feb 2016 Vol. 12 (2) p 145-e117). Seven medical and one biomedical science student enrolled to complete the Sep-Dec 2016 course. Weekly sessions, facilitated by an Oncologist, utilize independent and collaborative learning, small group role playing, concept maps, algorithms and multiple case scenarios to identify and analyze key issues of survivorship. Co-facilitators with varied expertise and cancer survivors are invited weekly. Successful completion requires active participation, reading and discussion of r...
Clinical Colorectal Cancer, Aug 1, 2001
PubMed, 1994
Recently, a method for the direct labeling of antibodies with 99mTc was described in which sulfhy... more Recently, a method for the direct labeling of antibodies with 99mTc was described in which sulfhydryls were reportedly generated by reduction of antibody disulfides with ascorbic acid. Thereafter, these proteins may be labeled at high efficiency with 99mTc following reduction of pertechnetate with dithionite. This investigation was initially conducted to evaluate the mechanism of the increased stability towards cysteine challenge reported for the label and subsequently to determine the role of ascorbate in the labeling process. Methods: It was possible to reproduce the reported high labeling efficiencies by increasing the dithionite concentration fivefold, presumably because of variabilities among lots of commercial sodium dithionite. Results: Despite success in labeling, it was not possible to confirm that antibody reduction followed the treatment with ascorbate. Using both Ellman's reagent and 2,2' dithiodipyridine as indicators, we were unable to detect sulfhydryls on one IgG antibody treated at ten times the suggested ascorbate-to-antibody molar ratio. It was estimated that the number of sulfhydryls generated could not have been more than 1% (dithiodipyridine) to 2% (Ellman's). Furthermore, radiolabeling efficiencies for two IgG antibodies and stabilities of the label to cysteine challenge were unchanged when the ascorbate was eliminated. The number of sulfhydryls generated by treatment of the antibody with dithionite at 1-2 times the concentration required for adequate labeling was about 1% (dithiodipyridine) to 5% (Ellman's). Conclusion: For the conditions of this investigation and for the antibodies employed, ascorbate apparently played no more than a minor role at best in the labeling process. If antibody reduction occurred, this most likely was a result of residual dithionite presented to the protein along with the reduced 99mTc.
PubMed, Jun 1, 1996
Methods for labeling antibodies with 99mTc cannot be used without modification for radiorhenium d... more Methods for labeling antibodies with 99mTc cannot be used without modification for radiorhenium despite the similar chemistries, in part because of a lower redox potential of rhenium and therefore a greater tendency to reoxidize. We have investigated conditions for directly labeling B72.3 IgG with 188Re via both mercaptoethanol and stannous ion antibody reduction. The reduced 188Re was stabilized for transchelation as the glucoheptonate complex and transchelated in the presence of excess stannous ion. End points were low "non-specific" binding (i.e. labeling in the absence of antibody reduction) and increased stability to cysteine challenge. By both methods, labeling efficiencies after about 15 minutes averaged 58.77% with as little as 4% non-specific binding. Specific activities of 15 muCi/microgram was achieved after 1.5 hours. By investigating labeling condition, it was possible to improve the stability of the label on stannous ion reduced antibody such that the in vitro and in vivo properties of 188Re were largely independent of labeling method. For example, losses of 188Re due to oxidation (16%) and to cysteine (7%) during 37 degrees C serum incubations for 24 hours were identical for both methods. Furthermore, after the administration to normal mice, whole body clearance and the accumulations of 188Re at 2.5 and 24 hours in blood and in most organs were also independent of labeling method. In conclusion, two different direct labeling methods provided a 188Re-labeled antibody with identical stabilities and with in vivo properties not greatly different from that seen for the same antibody radiolabeled directly with 99mTc.
PubMed, 1996
Oligonucleotides, particularly single stranded, may ultimately be of considerable use as radiopha... more Oligonucleotides, particularly single stranded, may ultimately be of considerable use as radiopharmaceuticals. We have compared a synthetic 22-base single-stranded phosphodiester DNA with its phosphorothioate analog after both were radiolabeled with 99mTc via the hydrazino nicotinamide chelator. Whole body clearance of the label in mice was much slower when introduced on the phosphorothioate (30% vs. 75% clearance at 6 hr) because of immediate and persistent accumulation in liver (47% vs. 2% injected dose/g at 4 hr). The label in both cases was present in urine primarily on low molecular weight catabolites. High-performance liquid chromatography analysis of 37 degrees C serum incubates showed serum protein binding of 99mTc in both cases (about 100% bound at 24 hr) but to different proteins. Different behavior with respect to protein binding was also observed in the analysis of liver and kidney homogenates: the phosphodiester label was almost quantitatively converted to lower molecular weight catabolites after only 15 min, whereas the phosphorothioate label was primarily on proteins. The rapid digestion of the phosphodiester by nucleases was not observed, probably because protein binding of the labeled oligonucleotides stabilized against degradation. Thus the phosphodiester DNA may be the preferred 99mTc-labeled oligonucleotide in certain circumstances to avoid the high and persistent liver uptake observed with the phosphorothioate DNA.
PubMed, Dec 1, 1995
Single-stranded RNA and DNA oligonucleotides may be useful as radiopharmaceuticals for antisense ... more Single-stranded RNA and DNA oligonucleotides may be useful as radiopharmaceuticals for antisense and other in vivo applications if convenient methods for stably attaching radionuclides such as 99mTc can be developed. Methods: To radiolabel DNA with 99mTc, we have used the hydrazino nicotinamide (SHNH) moiety developed elsewhere. The diethylenetriaminepentacetic acid (DTPA) chelate was used to label DNA with 111In for comparison. Complementary 22-base, single-stranded oligonucleotides were obtained, each with a primary amine attached to either 3' or 5' end with a biotin moiety on the opposite end. The DNA was conjugated with SHNH by a N-hydroxysuccinimide derivative with DTPA by the cyclic anhydride. Results: Reversed-phase HPLC analysis showed that essentially complete conjugation was achieved in both cases. The purified SHNH-DNA was radiolabeled with 99mTc by transchelation from glucoheptonate at labeling efficiencies of up to 60% and DTPA-DNA with 111In acetate at up to 100% efficiency. After labeling, the ability of the DNAs to bind to streptavidin through the biotin moieties and to hybridize with their complementary DNA in saline was retained for both radiolabels as determined by size-exclusion HPLC analysis. HPLC radiochromatograms of serum incubates showed a shift to 99mTc, but not 111In, to a high molecular weight, strongly suggesting serum protein binding in the former case only. Low-molecular weight degradation products were seen with 111In, but not with 99mTc and may be related to the use of phosphodiester-linked oligonucleotides. As a further measure of label stability, the DNAS were bound to streptavidin-conjugated magnetic beads and incubated in fresh 37 degrees C human serum. Less than 4% of 99mTc and 14% of 111In was lost in 24 hr. Conclusion: Amino-modified, single-stranded DNA can be stably radiolabeled with 99mTc by the SHNH moiety without loss of function.
PubMed, 1993
To investigate the in vivo and in vitro properties of 99mTc when labeled to antibodies via one di... more To investigate the in vivo and in vitro properties of 99mTc when labeled to antibodies via one direct and one indirect method, the B72.3 and C110 IgG antibodies were radiolabeled directly via stannous ion reduction and indirectly via the hydrazino nicotinamide chelator and compared in vitro and in vivo. Antibody avidity (but not immunoreactive fraction) appeared to be independent of labeling methods for both antibodies. Following stannous ion reduction, antibodies were fragmented by denaturing SDS PAGE although only slight evidence of fragmentation was found in vivo. The direct label was instable to transchelation to cysteine and glutathione in vitro and in vivo. Following intravenous administration, urinary excretion of activity was threefold greater for the direct label and was almost exclusively labeled cysteine and glutathione. Significant differences in the biodistribution of 99mTc were also observed: liver levels were lower, kidney levels were higher and clearance of label from blood and tissues was faster for the direct label. At Day 1, tumor accumulation was threefold lower for the direct label although most normal tissues were also lower. In conclusion, when labeled to two antibodies by one direct method, 99mTc is unstable towards transchelation relative to one indirect method. These relative instabilities greatly influenced the biodistributions in mice and may influence the quality of images obtained in patients.
Journal of Clinical Oncology, Jun 1, 2023
Journal of Immunotherapy, Aug 1, 1994
Nuclear Medicine and Biology, Nov 1, 1994
Recent investigations have shown that transchelation to cysteine is a principal mode of in viva i... more Recent investigations have shown that transchelation to cysteine is a principal mode of in viva instability of *"Tc-labeled antibodies. In this investigation, a cysteine challenge assay was used to measure the in vitro instability of *Tc directly labeled to two IgG antibodies (B72.3 and Cl 10) via two established direct labeling methods employing mercaptoethanol and stannous ion for antibody reduction and by a novel method using glutathione for this purpose. For both antibodies, the greatest instability to cysteine occurred with stannous ion reduction. The stability of glutathione-reduced B72.3 was indistinguishable from mercaptoethanol-reduced B72.3 whereas glutathione-reduced Cl 10 showed stability roughly intermediate between that of the other reducing agents for this antibody. Results obtained in normal mice were in the direction predicted by the assay: for both antibodies, urinary clearance of %Tc was fastest in mice receiving antibodies labeled via stannous ion reduction, presumably because of the increased transchelation of label to cysteine in uivo. Urinary clearance was slower and identical in mice receiving B72.3 labeled via glutathione or mercaptoethanol whereas clearance in the case of glutathione-reduced Cl10 was intermediate between that of the other two reducing agents. At both time points, higher radioactivity levels were observed in kidneys and lower levels in blood and most other tissues for both antibodies in the case of stannous ion reduction as expected for the label of greatest instability. In the B72.3 case, with only one exception, tissue and blood levels following administration of glutathione-reduced antibody were indistinguishable from that following administration of mercaptoethanol-reduced antibody. In the Cl 10 case, significant differences in activity levels were observed in several tissues between glutathione-and mercaptoethanol-reduced antibodies. In conclusion, the relative in vivo behaviour of %'"Tc when administered to mice while labeled to two IgG antibodies were successfully predicted based on the results of an in vitro cysteine challenge assay.
Annals of Emergency Medicine, 2021
Nuclear Medicine Communications, 1995
Bioconjugate Chemistry, 1995
Consideration is now being given to the use of avidin (or streptavidin) and biotin for radiothera... more Consideration is now being given to the use of avidin (or streptavidin) and biotin for radiotherapy of tumor. Accordingly, the goal of this study was to radiolabel a mouse metallothionein-streptavidin fusion protein with 188Re and to compare its properties to those of the same fusion protein radiolabeled with 99mTc. A recombinant metallothionein-streptavidin fusion protein was radiolabeled by transchelation with 99mTc- and 188Re-glucoheptonate. Labeling efficiency, which was not optimized for either radionuclide, was approximately 60% for 99mTc and 20% for 188Re. Radiochemical purity was demonstrated by size exclusion HPLC both by nearly quantitative shifts of the 188Re label to higher molecular weight upon the addition of biotinylated antibody and by the absence of a shift with biotinsaturated 188Re-metallothionein-streptavidin. Stability of the labels in 37 degrees C serum was evaluated by comparing the HPLC radiochromatograms of serum samples both before and after the addition of biotinylated antibody. The 188Re label behaved like 99mTc in that the same peaks were evident, including one prominent peak due to labeled cysteine. Recoveries during HPLC analysis of serum samples showed that oxidation rates to perrhenate and pertechnetate were identical. However, instability to cysteine challenge was greater for 188Re; for example, the loss of label to cysteine after 24 h under one set of conditions was 41% for 188Re and 22% with 99mTc. Analysis by HPLC of liver and kidney homogenates from mice administered the labeled antibodies were qualitatively and, in large measure, quantitatively independent of label. Biodistributions at 5 h in normal mice were statistically identical between the two labels in blood and in most tissues. In conclusion, streptavidin may be radiolabeled with radiorhenium using recombinant mouse metallothionein as a bifunctional chelator, and under one set of labeling conditions at least, 188Re showed similar in vitro and in vivo behavior to that of 99mTc labeled to the same fusion protein.
Orvosi hetilap, Jan 18, 1994
The authors summarize the recent findings obtained in the field of inflammatory cytokines with pa... more The authors summarize the recent findings obtained in the field of inflammatory cytokines with particular attention on interleukin-6 (IL-6). After a short review of the molecular biology and of the cellular effects of IL-6, the most important clinical relations of IL-6 in hepatic diseases, in non-specific inflammatory bowel diseases (Crohn's disease and ulcerative colitis) and in certain autoimmune diseases are provided. The simultaneous discussion of molecular and clinical data contribute to the understanding of pathomechanisms.
Journal of nuclear medicine : official publication, Society of Nuclear Medicine, 1996
Animal studies of infection imaging by a two-step protocol have shown that important improvements... more Animal studies of infection imaging by a two-step protocol have shown that important improvements in target to nontarget ratios are possible. In this protocol, unlabeled streptavidin is administered and allowed sufficient time to accumulate in the lesion, probably by nonspecific processes, and to clear elsewhere. Thereafter, 111Inbiotin is administered. A fraction of the labeled biotin may be retained in the lesion because of biotin's high affinity for streptavidin while most of the activity is cleared through the kidneys. Radioscintigraphy with unlabeled streptavidin followed with 111Inlabeled biotin was performed in 15 patients with chronic osteomyelitis. As controls, each patients received either 111In-labeled biotin without the preadministration of streptavidin or 111In-labeled nonspecific IgG. Regions of focal uptake were identified in all patients receiving streptavidin followed by radiolabeled biotin as early as 10 min postadministration of radioactivity, and retention of...
Education Sciences
Sound foundational knowledge improves disease conceptualization and clinical diagnosis. Vertical ... more Sound foundational knowledge improves disease conceptualization and clinical diagnosis. Vertical integration (VI) is an appealing educational strategy to refresh relevant pre-clinical information during clinical rotations. However, an optimal learning approach for this has not yet been established. We hypothesized that a small group collaborative discussion format might serve as an appealing learning method to deliver integrated material and increase retention. During AYs 2018/2019 and 2019/2020, our multidisciplinary team utilized a Colorectal Cancer workshop incorporating pre-clinical material for Y3 students on Surgical Clerkship. In search of an optimized way to deliver vertically integrated content, we alternately presented the workshop material either in a small group (SG) case-based collaborative format or as a standard-sized group (StdG) exercise. We achieved this by testing immediate and late (4-week post-event) recall and assessing student satisfaction with the VI strategy...
Journal of Leukocyte Biology
ABSTRACT
PLOS ONE, 2022
Background and objectives Human trafficking is a significant problem in which healthcare workers ... more Background and objectives Human trafficking is a significant problem in which healthcare workers are in a unique position to intervene. This study sought to determine the self-reported knowledge levels of healthcare providers most likely to come in direct contact with victims of human trafficking. Methods An anonymous survey assessing self-reported knowledge of human trafficking was developed and distributed online. Demographic information and questions pertaining to training and knowledge of trafficking in a healthcare setting were asked. The primary outcomes were descriptive statistics and secondary outcomes were comparisons among demographic groups. Qualitative methodology via content analysis was implemented on an open-ended question. Results The 6,603 respondents represented all regions of the country. Medical, nursing, and physician assistant students comprised 23% of the sample, while 40% were either physicians, fellows, or residents. Less than half the respondents (42%) have...
Journal of Leukocyte Biology, 1992
To test our hypothesis that monocytes (M phi) and their mediators are major contributors to ethan... more To test our hypothesis that monocytes (M phi) and their mediators are major contributors to ethanol-related immunodepression, the modulating capacity of acute ethanol treatment was assessed on the production of transforming growth factor-beta (TGF beta) and prostaglandin E2 (PGE2) by human peripheral blood M phi. We demonstrate that acute in vitro treatment of adherent M phi with either 50 or 150 mM ethanol induced a significant increase in the production of TGF beta (P < 0.045 and P < 0.001, respectively). Furthermore, M phi pretreatment with both 50 and 150 mM ethanol augmented TGF beta production in response to subsequent stimulation with the synthetic bacterial analog, muramyl dipeptide (MDP) (P < 0.05 and P < 0.001, respectively). Ethanol also increased TGF beta production in interferon gamma (IFN gamma-activated M phi in response to MDP stimulus (P < 0.05). M phi TGF beta levels, however, were always lower in IFN gamma-activated than in non-IFN gamma-activated M phi after the same stimulation with ethanol plus MDP, suggesting that M phi preactivation by IFN gamma can partially counteract the TGF beta inducing potential of ethanol. Similar to its TGF beta-inducing potential, ethanol (150 mM) had the capacity to induce PGE2 production in adherent human M phi (P < 0.045). However, ethanol failed to augment M phi PGE2 production induced by the PGE2 secretagogue, MDP. TGF beta induction by ethanol was unaffected by the presence of cyclooxygenase inhibitor, suggesting that ethanol-induced M phi TGF beta production does not require M phi PGE2 production. These results indicate that ethanol is a potent inducer for inhibitory M phi mediators, TGF beta and PGE2, and also has the capacity to augment M phi TGF beta production in response to subsequent stimulation. Thus, ethanol-induced elevation of M phi TGF beta and PGE2 production might contribute to decreased T cell proliferation and abnormal M phi functions after alcohol exposure, resulting in a depressed immune response.
Cureus, Jan 22, 2018
Longevity in cancer patients with brain metastases is increasingly being observed. This raises di... more Longevity in cancer patients with brain metastases is increasingly being observed. This raises discussions about how best to maintain a good quality of life for these patients. Recent data suggest that post-treatment quality of life (QoL) can be maintained using new treatment options, but little data exist regarding the QoL in long-term survivors. This study of 19 patients surviving greater than two years from the initial treatment of brain metastases suggests that long-term QoL can be better than at the start of treatment and perhaps even better than normal, especially between three and five years post-treatment. This improved QoL seems mostly attributable to improved functional and social well-being and is possible as long as emotional and physical well-being are maintained within the normal range.
Journal of Clinical Oncology, 2017
15 Background: Responding to calls for education in Cancer Survivorship, the Frank H. Netter MD S... more 15 Background: Responding to calls for education in Cancer Survivorship, the Frank H. Netter MD School of Medicine introduced new content using an interactive student elective for Y2 medical students with the goal of improving medical knowledge and confidence in caring for survivors. Methods: Learning objectives and course content were developed based upon the ASCO curriculum (ASCO Core Curriculum for Cancer Survivorship Education Shapiro, CL et al, Journal of Oncology Practice Feb 2016 Vol. 12 (2) p 145-e117). Seven medical and one biomedical science student enrolled to complete the Sep-Dec 2016 course. Weekly sessions, facilitated by an Oncologist, utilize independent and collaborative learning, small group role playing, concept maps, algorithms and multiple case scenarios to identify and analyze key issues of survivorship. Co-facilitators with varied expertise and cancer survivors are invited weekly. Successful completion requires active participation, reading and discussion of r...