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Gallium-67 scanning is a useful tool to search for infectious foci and malignant tumors. Multiple myeloma is one clinical indication for gallium-67 tumor survey. Here, we report a rare case of diffuse multiple cutaneous plasmacytomas from recurrent multiple myeloma, demonstrated by whole-body gallium-67 scan.
Column-switching liquid chromatography followed by low-resolution ICPMS was evaluated as a tool for speciation analysis of metal-containing biomolecules. The strategy was applied on siderophores, strong iron chelators of low molecular weight (M(w) < 1500). Prior to the LC-ICPMS analysis, reductive displacement of iron by gallium was performed using ascorbate as the reducing agent to increase the sensitivity. Different experimental conditions during the exchange reaction were tested using ferrichrysin and ferrichrome for evaluation. A reaction time of 30 min and a pH of 3.9 gave an exchange yield of 27 and 83% for ferrichrysin and ferrichrome, respectively. A gradient elution profile was also developed to separate gallium-chelated siderophores on a PGC column. Detection limits for standard solutions of ferrichrysin and ferrichrome in the low-nanomolar range were obtained by monitoring the gallium-69 isotope. The combined use of LC-ICPMS and LC-ESI-MS/MS was also evaluated as a tool to identify unknown metal complexes, here siderophores, in field soil solution samples.
A tripodal bifunctional chelator for gallium has been prepared with a chelation core consisting of three thiols and a tertiary amine. The synthesis proceeds in 13 steps with an overall yield of 22%. An aromatic amine is available for conjugation to peptides through carbodiimide coupling. Gallium(III) complexes were readily prepared from both the bifunctional chelator and a phenylalanine-conjugated system. These complexes underwent stability evaluation and were found to be stable to ligand exchange and enzymatic hydrolysis. This bifunctional chelator appears to be suitable for conjugation to peptides for the preparation of gallium radiopharmaceuticals.
Gallium and indium complexes with pendant carbohydrates have been prepared and examined for their potential as radiopharmaceuticals. Carbohydrate-bearing 3-hydroxy-4-pyridinone ligand precursors and their tris(ligand)gallium(III) and -indium(III) complexes were synthesized and characterized by mass spectrometry, elemental analysis, and (1)H and (13)C NMR spectroscopy, and in the case of one intermediate, by X-ray crystallography. With three equivalents of ligand, neutral complexes formed with the bidentate hydroxypyridinone moiety complexing the gallium(III) and indium(III) metal centers.
A fusion protein made from maltose binding protein (pmal) and human metallothionein (MT) was expressed using E. coli. The purified recombinant protein (pmal-MT) was immobilized on Chitopearl resin, and characteristics of pmal-MT for metal binding were evaluated. As expected from the tertiary structure of metallothionein, the pmal-MT ligand adsorbed 12.1 cadmium molecules per one molecule of the ligand at pH 5.2. The pmal-MT ligand also bound 26.6 gallium molecules per one molecule of the ligand at pH 6.5. Neither cadmium ion nor gallium ion bound to a control protein bovine serum albumin (BSA). Adsorption isotherms for both ions were correlated by Langmuir-type equations. Two types of binding sites have been elucidated on the basis of HSAB (hard and soft acid and base) theory. It was suggested that gallium ion specifically binds to amino acid residues containing oxygen and nitrogen atoms, while cadmium ion binds to specific binding sites formed by multiple cysteine residues. The pmal-MT ligand bound these metals in the concentration range of 0.2-1.0 mM, and the bound metal ions could be eluted under relatively mild conditions (pH 2.0). The pmal-MT Chitopearl resin was stable and could be used repeatedly without loss of binding activity. Thus, this new ligand would be useful for recovery of toxic heavy metals and/or valuable metal ions from various aqueous solutions.
The reactions of the anionic gallium(I) N-heterocyclic carbene (NHC) analogue, [K(tmeda)][:Ga{[N(Ar)C(H)]2}], Ar = C6H3Pri2-2,6, with the heavier group 14 alkene analogues, R2E=ER2, E = Ge or Sn, R = -CH(SiMe3)2, have been carried out. In 2:1 stoichiometries, these lead to the ionic [K(tmeda)][R2EGa{[N(Ar)C(H)]2}] complexes which exhibit long E-Ga bonds. The nature of these bonds has been probed by DFT calculations, and the complexes have been compared to neutral NHC adducts of group 14 dialkyls. The 4:1 reaction of [K(tmeda)][:Ga{[N(Ar)C(H)]2}] with R2Sn=SnR2 leads to the digallyl stannate complex, [K(tmeda)][RSn[Ga{[N(Ar)C(H)]2}]2], presumably via elimination of KR. In contrast, the reaction of the gallium heterocycle with PbR2 affords the digallane4, [Ga{[N(Ar)C(H)]2}]2, via an oxidative coupling reaction. For sake of comparison, the reactions of [K(tmeda)][:Ga{[N(Ar)C(H)]2}] with Ar'2E=EAr'2, E = Ge, Sn or Pb, Ar' = C6H2Pri3-2,4,6, were carried out and led to either no reaction (E = Ge), the formation of [K(tmeda)][Ar'2SnGa{[N(Ar)C(H)]2}] (E = Sn), or the gallium(III) heterocycle, [Ar'Ga{[N(Ar)C(H)]2}] (E = Pb). Salt elimination reactions between [K(tmeda)][:Ga{[N(Ar)C(H)]2}] and the guanidinato group 14 complexes [(Giso)ECl], E = Ge or Sn, Giso = [Pri2NC{N(Ar)}2]-, gave the neutral [(Giso)EGa{[N(Ar)C(H)]2}] complexes. All complexes have been characterized by NMR spectroscopy and X-ray crystallographic studies.
A series of 10 cationic gallium(III) complexes with hexadentate bis(salicylaldimine) ligands were synthesized, characterized, radiolabeled with 67Ga, and screened in a rat model to assess their potential as 68Ga radiopharmaceuticals for imaging the heart with positron emission tomography. The tris(salicylaldimine) ligand precursors were synthesized by condensation of either bis(3-aminopropyl)ethylenediamine (BAPEN) or bis(2,2-dimethyl-3-aminopropyl)ethylenediamine (DM-BAPEN) with 3 equiv of a salicylaldehyde derivative containing alkyl, alkoxy, or alkylamino substituents in the 4, 5, or 6 position of the aromatic ring. The cationic six-coordinate gallium(III) bis(salicylaldimine) complexes were obtained by reaction of these tris(salicylaldimines) with tris(acetylacetonato)gallium(III). X-ray crystallographic confirmation of the molecular structure of Ga[(4,6-(MeO)2sal)2DM-BAPEN]+I- shows the Ga cation to adopt a pseudo-octahedral N4O2 coordination sphere with a trans configuration. All of the 67Ga complexes are lipophilic with measured octanol/water partition coefficients (P) varying from log P = 0.84 to 3.00. These 67Ga-labeled complexes are all found to exhibit significant myocardial uptake following intravenous administration to rats (ranging from 0.34 to 1.08% of the injected dose in myocardium at 1 min postinjection) combined with the desired myocardial retention of tracer.
Gallium binds to the iron transport protein transferrin (Tf), is incorporated into cells through transferrin receptors (TfR) and inhibits iron-dependent DNA synthesis. Since cellular TfR expression is tightly regulated by the availability of iron, we investigated the effects of transferrin-gallium (Tf-Ga) on TfR mRNA levels in myeloid HL60 and lymphoid CCRF-CEM cells. In HL60 cells, Tf-Ga increased TfR mRNA levels in a dose-dependent fashion. This increase in TfR mRNA was blocked by Tf-Fe and by cycloheximide. Analysis of the rate of mRNA decay in the presence of actinomycin D revealed that the half-life of TfR mRNA was increased in HL60 cells incubated with Tf-Ga. The rate of transcription of TfR mRNA was not increased by Tf-Ga. In contrast with HL60 cells, CCRF-CEM cells displayed a decrease in the level of TfR mRNA after incubation with Tf-Ga. Tf-Ga inhibited iron uptake in both HL60 and CCRF-CEM cells but increased the level of TfR mRNA only in HL60 cells, suggesting that the Tf-Ga induction of TfR mRNA was not solely due to inhibition of cellular iron uptake. At growth-inhibitory concentrations, Tf-Ga increased the TfR mRNA level in HL60 cells but decreased it in CCRF-CEM cells. Our studies suggest that in HL60 cells, gallium regulates TfR expression at the post-transcriptional level by mechanisms which require de novo protein synthesis and involve interaction with iron. The divergent effects of Tf-Ga on TfR mRNA in myeloid HL60 and lymphoid CCRF-CEM cells suggest that differences exist in the regulation of TfR expression between these two cell types.
The aim of the current study was to compare the handling characteristics of a palladium-free gallium-based alloys (Galloy) with those of a high-copper amalgam (Permite C). The study had a particular interest in the evaluation of the direct placement delivery system used with both alloys. Ten dentists participated in the current study. Each placed two amalgam and two gallium-based alloy restorations in conventional class II cavities prepared in acrylic typodont teeth. None of the participating dentists had used the direct placement delivery system or had any previous experience with gallium-based alloy and no practice was allowed beforehand. The restorations were evaluated according to the following criteria: ease of loading the cavity (delivery system), ease of condensation, capacity to produce and sustain contact area, ease of carving, resistance to damage during removal of the matrix band, overall quality of the restoration and the available working time. Each criterion was given a score on a scale of 1-5 (1: very poor, 2: poor, 3: fair, 4: good, 5: very good). The results showed no statistically significant difference in the evaluated criteria between the two alloys (P > 0.05) except for criterion number 2 (ease of condensation, P=0.0005).
The results in the use of Gallium-scintigraphy for diagnosis of osteomyelitis are reported. The examined cases all had individual problems and the Gallium-67 promised additional information about the nature of the underlying bone process. Because of the different mechanisms for Gallium to accumulate in pathological bone processes it is necessary to know exactly the individual problem of the case to keep the rate of wrong positive results low. Despite of such efforts one should be cautious in using this method in the diagnosis of chronic osteomyelitis.
Metallothionein genes (MT) are inducible by a variety of agents, including heavy metals. We report the induction of MT expression by gallium arsenide (GaAs), a superior intermetallic semiconductor material at two time intervals following single oral exposure in rats. The data is also supplemented with two additional groups exposed to gallium (III) as gallium oxide and arsenic (III) as sodium arsenite to determine which of the two moieties in GaAs is responsible for any such possible effects. The results indicate that GaAs administration does significantly induces MT in hepatic tissues accompanied by an increase in cytosolic glutathione, arsenic, zinc and copper concentration. It thus proves that arsenic moiety is chiefly responsible for such an effect.
Crystalline particles of gallium arsenide (GaAs) (approximately 2 microns in diameter) react with concentrated hydrochloric acid (HCl) (11.6 to 9 M) to form highly toxic arsine (AsH3) gas. None of the other strong acids that were investigated reacted with gallium arsenide to form AsH3. A spectrophotometric method, based on the reaction of AsH3 with silver diethyldithiocarbamate in a chloroform solution containing morpholine, was used to detect AsH3 gas dissolved in aqueous solutions and to determine the AsH3 gas that was liberated by the reaction of GaAs with HCl. Active sites on the gallium arsenide surface initiate the reaction that forms AsH3 gas. Absorption of oxygen or ions from solution on these active sites inhibits the formation of AsH3.
This report describes the diagnostic contribution of gallium-67 scintigraphy in 145 cases of fever of unknown origin (FUO) at University Hospital in Leuven, Belgium, in 1980-1989. A final diagnosis was established in 99 (68%) of the 145 cases. Sixty-three scans (43%) were normal, and 82 (57%) were abnormal; only 42 of the abnormal scans (29% of the total number of scans) were considered helpful in diagnosis. Thus 49% of the abnormal scans were considered noncontributory to the diagnosis. In the same population, 15 (6%) of 266 ultrasonograms and 32 (14%) of 233 computed tomograms were helpful in diagnosis. We conclude that gallium scintigraphy remains a valuable screening tool in the investigation of FUO: it yielded diagnostic information in 29% of cases in which the probability of a definitive diagnosis was only 68%. We suggest the use of gallium scintigraphy as a second-step (as opposed to a last-resort) procedure in the evaluation of FUO.
A Phase II trial of gallium nitrate for patients with recurrent or metastatic nonsquamous cell carcinoma of the cervix was conducted by the Gynecologic Oncology Group (GOG) from March 1988 to January 1992. Twenty-six evaluable patients were treated with 750 mg/m2 of gallium nitrate every 3 weeks. Age range was 30-74 years with a median of 48 years. GOG performance status was 0-1 for all but four patients. Two patients had a complete response (7.7%), 1 patient had a partial response (3.8%), 13 patients had stable disease (50.0%), and 10 (38.5%) had increasing disease. The 95% confidence interval for response is 2.4-30.2%. The major toxicities were nausea, vomiting, and anemia. Gallium nitrate has modest activity in patients with nonsquamous cell carcinoma of the cervix.
Sternal osteomyelitis is an uncommon but serious complication of the median sternotomy incision. Between 1982 and 1990, 160 patients with sternal osteomyelitis and wound dehiscence were treated with sternal debridement and pectoral muscle flap closure at The Toronto Hospital. Most of these wound infections were clinically obvious, and the need for surgical treatment apparent. In a small number of patients, however, the extent of the infection was more difficult to determine clinically. In this subset of patients, the interpretation of the bone-gallium scan was important in determining the presence or absence of bone infection and the probability of successful treatment without surgery. In this study, we review our findings at the time of surgery and compare them with the preoperative information available from the bone-gallium scan. The limited literature on this topic is reviewed. In this group of patients, we found the bone-gallium scan was not helpful in clinical management.
In 18 of 88 children with biopsy proven and previously untreated Hodgkin's disease, recurrence developed during a period from four to 53 months after therapy (median period, 22 months). In 16 patients in whom gallium scans were performed, 21 positive gallium scans were obtained during 26 episodes of recurrence. Abnormalities were noted in half of them during a period from one to 10 months prior to physical, laboratory, radiographic or histologic confirmation of recurrence (median period about 5 months). We have concluded that the gallium scan is very useful in initial workup and is sensitive in detecting early recurrence in children with Hodgkin's disease. Such scans are indicated when there is clinical suspicion of recurrence, when other modalities are unavailable or when the results of other studies are equivocal.
Sequential gallium scans were performed in 37 patients with newly diagnosed osteogenic sarcoma. High gallium uptake was found more often in males in the 10 to 19 age group and in femoral lesions. High uptake was also seen in patients who had predominantly osteoblastic or mixed changes on radiographs and in those who had a soft tissue mass. Following chemotherapy, significant decrease of tumor to nontumor ratio occurred in the patients who responded to treatment as shown by a Grade III or IV response on histologic examinations at the time of en bloc resection. It is concluded that semiquantitative gallium scintigraphy is useful in monitoring therapeutic response in patients with osteogenic sarcoma.
Unilateral radionuclide accumulation in salivary glands is an uncommon finding on gallium scintigraphy. The differential diagnosis includes malignant tumors and inflammatory processes of these organs. Two cases of unilateral gallium uptake of the parotid and submandibular gland respectively, verified as solitary tuberculosis, are presented, together with the correlative findings of Tc-99m pertechnetate scintigraphy, sialography, and sonography. None of these imaging modalities is specific enough to provide pathognomonic signs for tuberculosis. When assessing unilateral gallium uptake of the salivary glands, one should be aware of the possibility of tuberculosis.