Abstract  In the direct labeling of antibodies with Re-186, 188, the lower redox potential of ReO4- than TcO4- requires the addition of excess SnCl2 and a medium-chelating agent for stabilizing the excess of SnCl2 in solution. Through extensive tests, sodium glucoheptonate (GH) was chosen as an excellent stabilizer for SnCl2 and also the reduced Re(V) from a variety of chelators, such as citrate, cyclodextrin, tartrate, inositol, glucose, glycine, etc. ReO4- solution was then quantitatively reduced for 2 h with newly prepared SnCl2(GH) solution. Then, we directly incorporated the reduced Re to the antibodies IgG modified with 135 ford of NaHSO3 and 3500 fold of 2-ME, and more than 90% of specific binding was yielded in 100-150 min at room temperature. TLC analysis indicated that less than 5% of activity was in the colloid form. Radiolabeled antibodies IgG were stable to the challenging of 700 fold of DTPA, and also showed fine in vivo stability.

Abstract  The effects of estradiol dipropionate (EDP) or calcium glucoheptonate (Ca) on the morphology and stereology of the PRL cells in 14-month-old Wistar female rats were studied. The animals were treated daily with EDP in the dose of 0.625 mg/kg b.w. or calcium glucoheptonate (Ca; 11.4 mg/kg b.w) for two weeks. The controls were injected with vehicle alone by the same schedule. Mammotrophs (PRL cells) were immunocytochemically localized by the PAP method. Blood PRL concentration was determined by Delfia procedure. In animals treated with EDP the volume of both, PRL cells and their nuclei, as well as the volume densities were significantly (p<0.05) increased by 17%, 9% and 38%, respectively, in comparison with the controls. In animals treated with Ca all morphometric parameters were insignificantly (p > 0.05) decreased compared to control rats. Serum concentration of PRL was significantly increased (p<0.05) by 17% after estradiol treatment, but in Ca-treated females this parameter was insignificantly (p>0.05) changed by 2% compared to controls. Based on these results, it can be concluded that EDP expresses a strong stimulatory effect on the morphology and function of pituitary PRL cells.

Abstract  The effects of multiple doses of estradiol dipropionate (EDP) or calcium glucoheptonate (Ca) on the growth and function of pituitary somatotropes (GH cells) were studied. Female middle-aged rats were receiving i.p. EDP (0.625 mg i.p./kg b.w), or Ca (11.4 mg/kg b.w) every day for two weeks. Blood samples were collected for hormone analyses and pituitaries dissected for histological and morphometric evaluation 24 h after the last injection. GH-producing cells were examined using the peroxidase-antiperoxidase (PAP) immunohistochemical procedure. Both EDP- and Ca-treatment significantly decreased all morphometric parameters of GH cells (p < 0.05) in comparison with the corresponding controls. Serum concentration of growth hormone (GH) in EDP- or Ca-treated groups was lower by 65% and 13% (p < 0.05) respectively, comparing to the controls. The difference between all morphometric parameters of EDPL and Ca-treated rats was statistically significant (p<0.05) in relation to the controls. These findings suggest that multiple EDP, or Ca application affects (directly or indirectly) the control of growth and secretory activity of GH cells in middle-aged female rats.

Abstract  The compatibility of dopamine hydrochloride (Intropin) with various additives in 5% Dextrose Injection, USP, was studied. Dopamine hydrochloride stability for 24 hours in the admixture was established by colorimetric and thin-layer chromatographic procedures. Dopamine hydrochloride solutions are generally stable at an acidic pH and all admixtures produced a slightly acidic solution. Additives tested and found stable for 24 hours in the presence of Intropin included heparin sodium, lidocaine hydrochloride, neutral cephalothin sodium, oxacillin sodium and gentamicin sulfate. The chemical stability of methylprednisolone sodium succinate and hydrocortisone sodium succinate was not established. Potassium chloride, calcium chloride and calcium gluceptate may be assumed to be stable in the presence of Intropin. Above pH 5.0, the calcium gluceptate-Intropin admixture exhibited a color change indicating physical incompatibility. The pH and physical compatibility of all admixtures were established. In order to avoid a fixed combination of potent drugs, it is recommended that a "piggyback" administration set or administration into a second injection site be employed when another drug is to be administered with Intropin.

Abstract  The pituitary TSH cell structure of middle-aged (14-month-old) female Wistar rats chronically treated with estradiol dipropionate (EDP), calcium glucoheptonate (Ca) or with the combination of both was studied. TSH-producing cells were examined in the pituitary pars distalis using rabbit anti-rat beta-thyrotropin (TSH) serum and peroxidase-antiperoxidase immunohistochemistry. A stereological method for the determination of morphometric changes of the volume of TSH cells and nuclei as well as of their number and relative volume densities was used. All examined morphometric parameters in treated animals showed a significant decrease in comparison with immunoreactive TSH cells of the controls; the most significant decrease was observed in EDP-treated rats. These results together with structural features of immunoreactive TSH cells in the pituitary of middle-aged rats after chronic application of EDP or Ca indicate that both compounds inhibit these cells.

Abstract  Solutions of glucoheptonate and sodium pertechnetate (Tc-99m) were subjected to electrolysis at various ampere-time products until a charge was found that consistently promoted tagging of greater than 90% efficiency. It was found that 9 coulombs (100 mA, 90 sec) consistently yielded a final product that contained less than 10% total radiochemical impurities (unbound pertechnetate and reduced, hydrolyzed technetium). Radiochemical purity of the final product was established using a two-solvent thin-layer chromatographic system with methyl-ethyl ketone and normal saline as the solvents. The tagging efficiency and stability of the tagged complex were determined with similar chromatographic analysis. It was shown that use of a 15% solution of calcium glucoheptonate resulted in a more stable product than that prepared from commercially available stannous glucoheptonate. The rapid, accurate chromatographic method for determination or radiochemical purity of the product is described. The final product is considered equal or superior to commercial Tc-99m (Sn) glucoheptonate and was produced at considerably less cost.

Abstract  The effect of calcitonin on pancreatic secretion was studied in unanesthetized dogs with a Thomas cannula implanted opposite the main pancreatic duct. Pancreatic juice was collected for a 60 minute control period, during which time secretion was stimulated by the intravenous infusion of secretin and pancreozymin. After the 60 minute control period, calcitonin was infused along with the secretin and pancreozymin. The infusion of calcitonin caused the volume, bicarbonate and enzyme output in the pancreatic juice to decrease to about one-half of that during the control period. During the one hour period, after calcitonin infusion was stopped, the volume, bicarbonate and enzyme content of the pancreatic juice increased but remained slightly lower than that of the control period. The infusion of calcium gluceptate, along with secretin and pancreozymin, overcame the inhibitory effect of calcitonin on pancreatic secretion.

Abstract  Monoclonal antibodies can be labelled with technetium-99m by prereduction of the antibody with 2-mercaptoethanol, then reduction of pertechnetate with an aliquot of a stannous kit, resulting in greater than 97% labelling without the need for further purification. The present work shows that equally high labelling can be obtained with a variety of weak ligands and that the optimum quantity of stannous chloride is 2-4 micrograms. Although the label was stable to challenge with excess DTPA, cysteine was able to remove a portion of the label. We have also shown that this technique works with the IgG2a isotype in addition to the previously reported IgG1 isotype. This approach is simple, convenient and reproducible, and warrants further clinical evaluation.

Abstract  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.

Abstract  A peptide glucuronide (Exorphin C glucuronide) was labeled with 99mTc using glucoheptonate (GH) as a bifunctional chelating agent. Scintigraphic imaging was performed in male Albino rabbits. Exorphin C glucuronide showed rapid and efficient labeling with 99mTc using glucoheptonate as a bifunctional chelate. Results demonstrated that 99mTc-GEG may be a useful new type of glucuronide derivative of peptides for diagnosis of some cancer diseases.

Abstract  Gelchromatography column scanning has been used to study the fractions of reduced hydrolyzed 99mTc, 99mTc-pertechnetate and 99mTc-chelate in a 99mTc-glucoheptonate (GH) preparation. A stable high labelling yield of 99mTc-GH complex in the radiopharmaceutical has been obtained with a concentration of 40-50 mg of glucoheptonic acid-calcium salt and not less than 0.45 mg of SnCl2.2 H2O at an optimal pH between 6.5 and 7.0. The stability of the complex has been found significantly affected when sodium hydroxide solution was used for the pH adjustment. However, an alternative procedure for final pH adjustment of the preparation has been investigated providing a stable complex for the usual period of time prior to the injection. The organ distribution and the blood clearance data of 99mTc-GH in rabbits were relatively similar to those reported earlier. The mean concentration of the radiopharmaceutical in both kidneys has been studied in normal subjects for one hour with a scintillation camera and the results were satisfactory.

Abstract  INTRODUCTION: Achieving an ideal (99m)Tc labeled nitroimidazole hypoxia marker is still considered to be of great interest. Metronidazole xanthate (MNXT) ligand was synthesized and radiolabeled with (99m)Tc-glucoheptonate (GH) to form the (99m)TcO-MNXT complex, for the potential use as a novel probe for imaging tumor hypoxia.

METHODS: For labeling, (99m)TcO-MNXT was prepared by ligand-exchange reaction with (99m)Tc-GH. The radiochemical purity of the (99m)TcO-MNXT complex was measured by thin layer chromatography (TLC) and high performance liquid chromatography (HPLC). The distribution coefficient and stability of the complex was investigated. The structure of the (99m)TcO-MNXT complex was verified by preparation and characterization of the corresponding stable rhenium complex. The cellular uptake of the (99m)TcO-MNXT complex was determined in murine sarcoma S180 cell lines under hypoxic and aerobic conditions. The biodistribution and single photon emission computed tomography (SPECT) image studies of the (99m)TcO-MNXT complex were performed in mice bearing S 180 tumor.

RESULTS: The radiochemical purity of the (99m)TcO-MNXT complex was over 90%. It had good in vitro stability and its distribution coefficient indicated that it was a hydrophilic complex. When (99m)Tc and Re complexes were coinjected in HPLC, both radioactivity (for (99m)Tc complex) and UV detectors (for Re complex) showed nearly identical HPLC profiles, suggesting their structures are similar. The tumor cell experiment and the biodistribution in mice bearing S 180 tumor showed that the (99m)TcO-MNXT complex had a good hypoxic selectivity and accumulated in the tumor with high uptake and good retention. Single photon emission computed tomography (SPECT) image studies showed that the tumor detection was observable.

CONCLUSIONS: (99m)TcO-MNXT is prepared from a kit without the need for purification and shows high tumor uptake, tumor/blood and tumor/muscle ratios, suggesting that it would be a promising candidate for imaging tumor hypoxia.

Abstract  A new method, based on the pretreatment of leukocytes with glucoheptonate prior to treating with reduced 99mTc, has been developed for the preparation of 99mTc labelled leukocytes. The leukocytes labelled with a 99mTc concentration (5.59%/g tissue) similar to that of 111In-leukocytes (6.27%/g tissue), in the experimental abscess were in rat thigh. Concentration of 99mTc-leukocytes in blood at 24 h was only about 35% as compared to that of 111In-leukocytes. Biodistribution in the rat organs was similar in both cases, except in the liver where 99mTc-leukocytes exhibited about 4-fold greater concentration. Images of experimental abscess in rat by using 99mTc-leukocytes were comparable to those obtained with 111In-leukocytes.

Abstract  INTRODUCTION: The purpose of this study was to examine whether (99m)Tc-labeled Arg-Gly-Asp (RGD)-conjugated alpha-melanocyte stimulating hormone (α-MSH) hybrid peptide targeting both melanocortin-1 (MC1) and α(v)β(3) integrin receptors was superior in melanoma targeting to (99m)Tc-labeled α-MSH or RGD peptide targeting only the MC1 or α(v)β(3) integrin receptor.

METHODS: RGD-Lys-(Arg(11))CCMSH, RAD-Lys-(Arg(11))CCMSH and RGD-Lys-(Arg(11))CCMSHscramble were designed to target both MC1 and α(v)β(3) integrin receptors, MC1 receptor only and α(v)β(3) integrin receptor only, respectively. The MC1 or α(v)β(3) integrin receptor binding affinities of three peptides were determined in M21 human melanoma cells. The melanoma targeting properties of (99m)Tc-labeled RGD-Lys-(Arg(11))CCMSH, RAD-Lys-(Arg(11))CCMSH and RGD-Lys-(Arg(11))CCMSHscramble were determined in M21 human melanoma-xenografted nude mice. Meanwhile, the melanoma uptake of (99m)Tc-RGD-Lys-(Arg(11))CCMSH was blocked with various non-radiolabeled peptides in M21 melanoma xenografts.

RESULTS: RGD-Lys-(Arg(11))CCMSH displayed 2.0 and 403 nM binding affinities to both MC1 and α(v)β(3) integrin receptors, whereas RAD-Lys-(Arg(11))CCMSH or RGD-Lys-(Arg(11))CCMSHscramble lost their α(v)β(3) integrin receptor binding affinity by greater than 248-fold or MC1 receptor binding affinity by more than 100-fold, respectively. The melanoma uptake of (99m)Tc-RGD-Lys-(Arg(11))CCMSH was 2.49 and 2.24 times (P < .05) the melanoma uptakes of (99m)Tc-RAD-Lys-(Arg(11))CCMSH and (99m)Tc-RGD-Lys-(Arg(11))CCMSHscramble at 2 h post-injection, respectively. Either RGD or (Arg(11))CCMSH peptide co-injection could block 42% and 57% of the tumor uptake of (99m)Tc-RGD-Lys-(Arg(11))CCMSH, whereas the coinjection of RGD+(Arg(11))CCMSH peptide mixture could block 66% of the tumor uptake of (99m)Tc-RGD-Lys-(Arg(11))CCMSH.

CONCLUSIONS: Targeting both MC1 and α(v)β(3) integrin receptors enhanced the melanoma uptake of (99m)Tc-RGD-Lys-(Arg(11))CCMSH in M21 human melanoma xenografts. Flank M21 human melanoma tumors were clearly visualized by single photon emission computed tomography/computed tomographic imaging using (99m)Tc-RGD-Lys-(Arg(11))CCMSH as an imaging probe, highlighting its potential use as a dual-receptor-targeting imaging probe for human melanoma detection.

Abstract  To determine the influence of varying molecular weight (mol wt) on respiratory clearance of aerosolized salutes, we studied eight radiopharmaceuticals, each administered to four dogs: sodium 99MTc pertechnetate (TcO4),99MTc glucoheptonate ([99M'Tc]GH), 51Cr-ethylenedinitrotetraacetate ([51Cr]EDTA), 99mTc diethylenetriaminepentaacetate ([99mTc] DTPA), 111In diethylenetriaminepentaacetate ([111In]DTPA), 67Ga desferoxaminemesylate ([67Ga]DFOM) 99mTc dextran ([99mTc]DX) and 111In transferrin ([1 11InJTF) After aerosolization (0.8 m MMD, 2.4 GSD), clearance was determined for 30 mm and then corrected by intravenous injection for nonairspace radioactivity. In-TF clearance (-0.11 ± 0.10 %/min) was lower than TcO4 (6.32 ± 0.62 %/min), [99mTc]GH (1.50 ± 0.37 0/o/min), [51Cr]EDTA (2.38 ± 1.02 %/min), [99mTc]DTPA (3.51 ± 0.40 %/min), [111In]DTPA (2.35 ± 0.42 %/min), [67Ga] DFOM (1.99 ± 0.49 %/min) and (99mTc]DX (1.81 ± 0.75 %/min) clearances (p < 0.001). TcO4 clearance was higher than others (p < 0.001). Technetium binding to DX was unsatisfactory; aerosolization caused unbinding from DTPA. We conclude that respiratory clearance of large mol wt salutes within 30 mm is negligible and, that clearance of molecules between 347-5,099 daltons differs greatly, suggesting that binding and/or intrapulmonary retention affect transfer.

Abstract  There have been extensive studies in sheep and cattle considering cobalt (Co) supplementation and its effects on vitamin B12 concentrations in the body. However, there are limited studies on goats. The aim of this study was to compare two different sources of Co (sulfate v. glucoheptonate) at two different concentrations (0.25 and 0.5 mg/kg dry matter) in goat kid nutrition, and to evaluate the effects of these supplements on performance, serum vitamin B12, blood biochemistry and rumen volatile fatty acids. For this purpose, 30 weaned male goat kids were randomly allotted to five treatments. Serum vitamin B12 increased during the trial in the Co-supplemented groups. Co supplementation increased serum glucose concentrations. On day 35, Co-supplemented groups had greater glucose concentrations compared with control. Propionic+iso-butyric acid concentrations increased only in the 0.5 mg Co glucoheptonate treatment (P<0.05). Our results suggest that, despite the two sources of Co proving mostly similar, the main advantage of Co glucoheptonate compared with Co sulfate was in the ruminal synthesis of vitamin B12. However, although providing Co at National Research Council recommendation levels maintained vitamin B12 above or at normal concentrations, Co supplementation of the Co sufficient basal diet increased vitamin B12 and glucose concentrations.

Abstract  A precipitate encountered in solutions of calcium gluceptate was identified as hydrated calcium gluceptate. Precipitation was associated with a change from a very soluble amorphous anhydrous form to a sparingly soluble crystalline hydrate, the presence of seed crystals inducing crystallization, and unsuitable proportions of the alpha- and beta-epimers of calcium gluceptate. Various commercial samples and the corresponding precipitates were examined by elemental analysis, thermal analysis, X-ray diffraction, IR spectroscopy, and GC-MS. The proportion of the alpha- and beta-epimers in commercial samples was quantitated by GC. In this method, an aqueous solution of calcium gluceptate was converted into a mixture of glucoheptonic acids and their corresponding lactones by passage through a cation-exchange resin. The solution was freeze-dried, the acid-lactone mixture converted to the gamma-lactones using concentrated hydrochloric acid, and the resulting material trimethylsilylated with trimethylsilylimidazole. Stability studies of solutions prepared from calcium gluceptate obtained from various commercial sources indicate that above approximately 50% alpha-epimer, stability decreased with an increase in the relative proportion of the alpha-epimer. Material complying with USP specifications (pure alpha-epimer) is the least stable in solution. It is suggested that calcium gluceptate containing approximately equal proportions of the alpha- and beta-epimers be introduced in the USP monograph together with a method for estimating the proportions of the epimers.

Abstract  Disruption of the blood-brain-barrier (BBB) is important in the pathophysiology of various inflammatory conditions of the central nervous system (CNS), such as multiple sclerosis (MS), in which breakdown of the BBB precedes any clinical or pathological findings. There is some evidence that relapsing-remitting MS attacks may be correlated with certain types of acute stressful episodes. Stress typically activates the hypothalamic-pituitary-adrenal (HPA) axis through the release of corticotropin releasing hormone (CRH), leading to production of glucocorticoids that down regulate immune responses. However, acute stress also has pro-inflammatory effects that appear to be mediated through activation of mast cells. Here we show that acute stress by immobilization increased permeability of rat BBB to intravenous 99Technetium gluceptate (99Tc). This effect was statistically significant in the diencephalon and the cerebellum, while it was absent in the cerebral cortex where there are not mast cells. Immobilization stress also induced activation of mast cells in diencephalon, the site where most mast cells are found in the rat brain. Both BBB permeability and mast cell activation were inhibited by the 'mast cell stabilizer' disodium cromoglycate (cromolyn). These results expand the pathophysiology of mast cells and implicate them in CNS disorders, that may possibly be induced or exacerbated by stress.

Abstract  OBJECTIVES: To evaluate the relative renal function on preoperative and postoperative renal scintigraphy with lateralized creatinine clearance. Multiple factors affect renal blood flow and glomerular filtration that alter the relative renal function calculated by renal scintigraphy. The relative renal function according to renal scintigraphy in children with bilateral vesicoureteral reflux has not been compared with lateralized creatinine clearance.

METHODS: We retrospectively reviewed the charts of 45 children treated surgically for bilateral vesicoureteral reflux. The average age at time of reimplantation was 5.3 years. Bilateral ureteral catheters were placed intraoperatively. Lateralized creatinine clearance was measured with 24-hour urine collections postoperatively from each catheter. Bladder catheterization was not performed during the renal scans.

RESULTS: Thirty-six of 45 children had preoperative 1 to 3-minute relative renal function assessed by scintigraphy, 28 had a postoperative assessment, and 24 had both. Preoperative relative renal function ranged between 51% and 94% (mean 61.3%) in the higher functioning kidney. Postoperative renal function ranged from 47% to 90% (mean 60.5%) in the higher functioning kidney. A strong correlation existed between preoperative relative renal function and lateralized creatinine clearance (P <0.0001). Similarly, a significant correlation existed between the postoperative assessment and lateralized creatinine clearance (P <0.0003). No significant difference occurred between the preoperative and postoperative 1 to 3-minute relative renal function (P = 0.3552).

CONCLUSIONS: The 1 to 3-minute relative renal function determined by renal scintigraphy accurately reflects the relative renal function determined by lateralized creatinine clearance. Bladder catheterization does not appear necessary for accurate determination of relative renal function by renal scan even in the presence of bilateral reflux.