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PubMed1993

Gallium-67 scintigraphy in tuberculous and nontuberculous infectious spondylitis.

Vertebral osteomyelitis is a difficult condition to diagnose clinically. A retrospective review of 21 cases of infectious spondylitis (6 tuberculous, 15 nontuberculous) confirmed the utility of 67Ga scintigraphy in imaging this process. Gallium-67 scans were positive at all sites of disease in this patient population. They anticipated the presence of spondylar infection in 23% of regions where radiographic abnormalities were originally lacking, while confirming a current and ongoing septic process at the other sites where vertebral destruction was already present on x-ray. Gallium-67 studies, as compared to the 99mTc-MDP bone scans, also provided important information as to the extent of disease by documenting the presence of eight paraspinal abscesses and the location of remote extraspinal foci of infection both in soft tissues and in bone. The relative merits of all radiologic imaging procedures are discussed. A diagnostic algorithm is also suggested.

Adolescent↗
PubMed1995

Abnormal gallium-67 skull uptake: a sign of peripheral marrow activation in HIV-positive patients with disseminated mycobacterioses.

UNLABELLED: The purpose of this study was to investigate the significance of abnormal 67Ga-citrate skull uptake in AIDS patients with mycobacterioses. METHODS: Gallium-67 scans of 39 HIV-positive patients who have been diagnosed with mycobacterioses were analyzed; the scans of 15 consecutive HIV-positive patients without mycobacterioses were also reviewed as a control group. The skull was chosen to assess bone marrow uptake because of the absence of overlapping structures. RESULTS: Twenty-nine of 39 (74%) patients with mycobacterial infections had disseminated disease. Gallium-67 uptake in the skull was visualized in 24 of these 29 patients (82%). One of the patients without disseminated disease and one patient in the control group (n = 15) showed skull uptake. CONCLUSION: Abnormal 67Ga skull uptake appears to be a sensitive (82%) and specific (82%) indicator of disseminated mycobacterial infection in HIV-positive patients.

AIDS-Related Opportunistic Infections↗
PubMed1996

Gallium-67 imaging of pericardial lymphoma in AIDS.

A 33-yr-old homosexual man with acquired immune deficiency syndrome (AIDS) and Mycobacterium avium intracellulare (MAI) infection presented with fever, sweats, lethargy and dyspnea. A chest radiograph showed cardiomegaly and an echocardiograph revealed a large pericardial effusion. After pericardial aspiration, which confirmed T cell non-Hodgkin's lymphoma, he remained dyspneic. Gallium-67 imaging was performed to determine whether the patient's residual dyspnea was related to pulmonary MAI infection or lymphomatous infiltration of the heart. Planar 67Ga scintigraphy revealed intense tracer uptake in two areas within the mediastinum and surrounding the entire heart shadow but no evidence of pulmonary MAI infection. SPECT 67Ga scintigraphy precisely localized the two mediastinal abnormalities and demonstrated the tracer uptake around the heart to be pericardial rather than myocardial. Gallium-67 scintigraphy suggested that pericardial lymphoma was the likely basis of the patient's dyspnea.

AIDS-Related Opportunistic Infections↗
PubMed1997

Vinblastine, ifosfamide, and gallium nitrate--an active new regimen in patients with advanced carcinoma of the urothelium. A phase II trial of the Eastern Cooperative Oncology Group (E5892).

BACKGROUND: This study was conducted to assess the efficacy and toxicity of vinblastine, ifosfamide, and gallium nitrate (VIG) as first-line chemotherapy in patients with locally advanced or metastatic carcinoma of the urothelium. METHODS: Forty-five eligible patients were enrolled and stratified into good and poor risk groups. Poor risk was defined as age > or = 70 years, 1 functioning kidney, and prior adjuvant or neoadjuvant chemotherapy. Good risk patients were treated with vinblastine, 0.11 mg/kg, on Days 1 and 2; ifosfamide, 1.2 g/m2, on Days 1-5 with mesna uroprotection; and gallium nitrate, 300 mg/m2, as a continuous infusion on Days 1-5. Poor risk patients received similar therapy with doses decreased by 20% and administered over 4 days. All patients received recombinant human granulocyte-colony stimulating factor. Cycles were repeated at 21-day intervals until disease progression or to a maximum of 6 cycles. RESULTS: Twenty of 45 patients (44%; 95% confidence interval, 30-60%) demonstrated an objective response, with 6 patients (13%) achieving a complete clinical response. The median duration of response was 47 weeks and the median survival duration for all patients was 10 months. Hematologic toxicity was significant, with 28 patients and 31 patients experiencing Grade 3 or 4 leukopenia and anemia, respectively. Six patients had clinically significant cardiac events (primarily atrial arrhythmias). There were two early deaths that were possibly treatment related. CONCLUSIONS: VIG is an active regimen in patients with advanced urothelial carcinoma. Toxicity is significant but acceptable. Patients with significant cardiac disease (especially arrhythmias) should be treated with extra care. The 4-day regimen appears to have similar therapeutic efficacy with less toxicity.

Adenocarcinoma↗
PubMedDate not supplied

In vitro corrosion behavior and microstructure examination of a gallium-based restorative.

Concerns of mercury toxicity have led to the development of gallium-based restorative materials to replace dental amalgam. A new gallium-based dental restorative, Galloy, was compared with a high-copper amalgam, Permite, for anodic polarization behavior in deoxygenated Ringer's solution and by immersion testing in normal Ringer's solution at 37 degrees C. Corrosion products were analyzed using energy dispersive X-ray spectrometry and transmission electron diffraction. The data from both sources were consistent with the presence of alpha-Ga2O3 and SnO2 as the primary corrosion products of Galloy. Anodic polarization behavior of Galloy- and Permite-coupled specimens suggests that coupling Galloy with the more noble Permite amalgam may cause accelerated electrochemical corrosion and that Galloy is more corrosion prone than Permite.

Corrosion↗
PubMed1976

Localization of gallium-67 citrate in salivary glands following radiation therapy.

Gallium-67 citrate was found to localize in the salivary glands of eight patients after therapeutic doses of radiation to a treatment field including the glands. In two patients, autopsy evidence to the effect that no primary disease was present to explain such uptake was obtained. In another two patients the abnormal uptake was not observed on follow-up. The recognition that radiation sialadenitis is a potential cause of false-positive gallium scintiscans is important in their interpretation.

Autopsy↗
PubMed1976

Localization of gallium-67 citrate in salivary glands following radiation therapy.

Gallium-67 citrate was found to localize in the salivary glands of eight patients after therapeutic doses of radiation to a treatment field including the glands. In two patients, autopsy evidence to the effect that no primary disease was present to explain such uptake was obtained. In another two patients the abnormal uptake was not observed on follow-up. The recognition that radiation sialadenitis is a potential cause of false-positive gallium scintiscans is important in their interpretation.

Autopsy↗
PubMed1998

Gallium restorative materials.

Gallium restorative alloys have been developed as an alternative to amalgam. When placed, with meticulous attention to moisture control, small restorations perform reasonably well in short-term clinical trials. However, tarnish and corrosion are pronounced. Results with large restorations are not impressive. Sealing of restorations, before and after placement, with a hydrophobic resin sealant is mandatory to prevent excessive expansion, post-operative sensitivity and tooth fracture. While the profession requires a less technique-sensitive alternative to silver amalgam than resin composite, for difficult and larger posterior situations, gallium alloys in their present state of development do not provide the answer. In fact, the manufacturer of Galloy has voluntarily withdrawn the product from the market, pending reformulation and development of new delivery systems.

Dental Alloys↗
PubMed1998

Gallium-67 scintigraphy to predict response to therapy in active lupus nephritis.

UNLABELLED: Gallium-67-citrate has been used to detect inflammation for decades, and 67Ga uptake usually indicates an active, potentially curable lesion. In this study, we determined the value of 67Ga renal scintigraphy for predicting response to therapy in patients with lupus nephritis. METHODS: Forty-seven patients with lupus nephritis and abnormal serum creatinine or elevated 24-hr urine protein were enrolled. Delayed 48-hr 67Ga imaging was performed to evaluate 67Ga uptake by the kidneys. Serum creatinine and 24-hr urine protein values were obtained at the beginning of this study and after 1 yr of treatment. Serum creatinine was considered abnormal at levels greater than or equal to 1.4 mg/dl and 24-hr urine protein at levels greater than or equal to 1.0 g/day. When the value of serum creatinine or 24-hr urine protein obtained 1 yr after treatment was in the normal range or was 50% of the initial abnormal value, the patient was considered to have good response to treatment. RESULTS: Gallium-67 renal scan showed good correlation with the response to therapy in patients with lupus nephritis. In the negative 67Ga scan group, no significant changes in laboratory data were noted between onset of this study and after 1 yr of therapy. In the positive 67Ga scan group, there were significant decreases in serum creatinine and 24-hr urine protein levels 1 yr after treatment, especially in 24-hr urine protein, with p values of 0.019 and 0.0007 respectively, by Student's t-test for dependent samples. Moreover, 11.5% of patients with a negative 67Ga scan had a good response to treatment, whereas 71.4% of patients with a positive 67Ga scan had a good response to treatment. CONCLUSION: We suggest that 67Ga renal scan is a valuable predictor of response to therapy in patients with lupus nephritis.

Adult↗
PubMed2001

[Ga18(SitBu3)8] and [Ga22(SitBu3)8]--syntheses and structural characterization of novel gallium cluster compounds.

The novel neutral gallium cluster compounds [Ga18R*8] (1) and [Ga22R*8] (2) are obtained by warming up a metastable solution of gallium(I) bromide in THF/C6H5CH3 after addition of equimolar amounts of supersilyl sodium NaR* from -78 degrees C to room temperature (R* = SitBu3 = supersilyl). From X-ray structure analyses, the observed arrangements of the 18 and 22 Ga atoms in 1 and 2, respectively, are comparable with an 18 atom section of the beta-Ga modification, or show at least some kind of relationship to a 22 atom section of the Ga-III modification. This allows a description of both the clusters as metalloid. The topology of the atoms in 2 is also well explained by the Wade-Mingos rules as an eightfold capped closo-Ga14 cluster, whereby the Ga atoms of Ga14 occupy the center and the corners of a cuboctahedron with one Ga3 face replaced by a Ga4 face. Some concepts are presented about the formation mechanism, the cluster growth, and the metalloid character of the two Ga cluster compounds.

Journal Article↗
PubMed2002

Metalloid aluminum and gallium clusters: element modifications on the molecular scale?

As members of the same group in the periodic table, the industrially significant elements aluminum and gallium exhibit strong similarities in the majority of their compounds. In contrast there are significant differences in the structures of the two elemental forms: Aluminum forms a typical closest-packed metallic structure whereas gallium demonstrates a diversity of molecular bonding principles in its seven structural modifications. It can therefore be expected that differences between Al and Ga compounds will arise when, as for the elemental forms, many metal-metal bonds are formed. To synthesize such cluster compounds, we have developed the following synthesis procedure: Starting from gaseous monohalides at around 1000 degrees C, metastable solutions are generated from which the elements ultimately precipitate by means of a disproportionation reaction at room temperature. On the way to the elemental forms, molecular Al and Ga cluster compounds can be obtained by selection of suitable ligands (protecting groups), in which a core of Al or Ga atoms are protected from the formation of the solid element by a ligand shell. Since the arrangement of atoms in such clusters corresponds to that in the elements, we have designated these clusters as metalloid or elementoid. In accordance with the Greek word [see text] (ideal, prototype), the atomic arrangement in metalloid clusters represents the prototypic or ideal atomic arrangement in the elements at the molecular level. The largest clusters of this type contain 77 Al or 84 Ga atoms and have diameters of up to two nanometers. They hold the world record with respect to the naked metal-atom core for structurally characterized metalloid clusters.

Journal Article↗
PubMed2006

The trinuclear gallium-bridged Ferrocenophane [{Fe(eta5-C5H4)2}3Ga2]: synthesis, bonding, structure, and coordination chemistry.

The trinuclear ferrocenophane [{Fe(eta(5)-C(5)H(4))(3)}(2)Ga(2)] (3) featuring two sp(2)-hybridized gallium atoms in bridging positions between three ferrocene-1,1'-diyl units represents a novel type of ferrocene derivative. Compound 3 is obtained by thermal treatment of 1,1'-bis(dimethylgallyl)ferrocene (1) in nondonor solvents or in diethyl ether as solvent and subsequent thermal decomplexation. The [1.1]ferrocenophane [{Fe(eta(5)-C(5)H(4))(2)}(2){GaMe}(2)] (2) is an intermediate in the formation of 3. The reaction of 3 with an excess of trimethylgallium leads back to 1 and proves the reversibility of the multistep reaction sequence. Theoretical calculations reveal a carousel-type D(3h) structure for 3. The compound can best be described as being composed of three only weakly interacting ferrocenediyl units covalently connected by gallium atoms without any pi-bond contribution in the Ga--C bonds. Owing to steric constraints 3 cannot be reduced to the dianion 3(2-), which would feature a Ga--Ga bond. Compound 3 represents a stereochemically rigid difunctional Lewis acid allowing the formation of the adducts 3 a-3 d possessing linear donor-aceptor-aceptor-donor arrangements. Crystal structure data for 3 a-3 d show a symmetry-reduced chiral ferrocenophane core (D(3h)-->D(3)). A polymeric rodlike structure is observed for 3 b and 3 d caused by pi-stacking effects (3 b) or by a difunctional donor-acceptor interaction (3 d). In solution, the chirality of the adducts is lost by rapid interconversion of the enantiomers. A cyclic voltammogram of 3 b in pyridine reveals three quasi-reversible oxidation steps at -356, -154, and 8 mV, indicating only weak electron delocalization in the cationic species. The redox potentials of the pyridine adduct 3 b are compared with those of other pyridine-stabilized gallyl-sustituted ferrocene derivatives and with ferrocene itself.

Journal Article↗
PubMedDate not supplied

Mapping piezoelectric-field distribution in gallium nitride with scanning second-harmonic generation microscopy.

Taking advantage of the electric field-enhanced second-harmonic generation effect in bulk gallium nitride (GaN) and indium gallium nitride (InGaN) quantum wells, we demonstrated the piezoelectric field distribution mapping in bulk GaN and InGaN multiple-quantum-well (MQW) samples using scanning second-harmonic generation (SHG) microscopy. Scanning SHG microscopy and the accompanying third-harmonic generation (THG) microscopy of the bulk GaN sample were demonstrated using a femtosecond Cr:forsterite laser at a wavelength of 1230 nm. Taking advantage of the off-resonant electric field-enhanced SHG effect and the bandtail state-resonance THG effect, the second- and third-harmonic generation microscopic images obtained revealed the piezoelectric field and bandtail state distributions in a GaN sample. Combined with 720 nm wavelength excited two-photon fluorescence microscopy in the same sample, the increased defect density around the defect area was found to suppress bandedge photoluminescence, to increase yellow luminescence, to increase bandtail state density, and to decrease residue piezoelectric field intensity. Scanning SHG microscopy of the InGaN MQW sample was resonant excited with 800 nm femtosecond pulses from a Ti:sapphire laser in order to suppress SHG contribution from the bulk GaN substrate. Taking advantage of the strong piezoelectric field inside the InGaN quantum well, the wavelength resonant effect, and the electric field-enhanced SHG effect of InGaN quantum wells, resonant scanning SHG microscopy revealed the piezoelectric field distribution inside the wells. Combined with accompanying three-photon fluorescence microscopy from the bulk GaN substrate underneath the quantum wells, the direct correspondence between the piezoelectric field strength inside the quantum well and the substrate quality can be obtained. According to our study, the GaN substrate area with bright bandedge luminescence corresponds to the area with strong SHG signals indicating a higher stained-induced piezoelectric field. These scanning harmonic generation microscopies exhibit superior images of the piezoelectric field and defect state distributions in GaN and InGaN MQWs not available before. Combining with scanning multiphoton fluorescence microscopy, these techniques open new ways for the physical property study of this important material system and can provide interesting details that are not readily available by other microscopic techniques.

Journal Article↗
PubMed2001

Pristine Points of Zero Charge of Gallium and Indium Oxides.

Electrokinetic measurements and potentiometric titrations of indium oxide (commercially available reagent grade powder, washed with NaOH and HNO(3) to remove strongly adsorbed species) indicate the pristine point of zero charge to be pH 8.7. The isoelectric point at pH 9 was obtained for gallium oxide prepared in the same way. These values match the pristine point of zero charge of alumina, but they are much higher than the values reported for indium oxide and gallium oxide in the literature. Copyright 2001 Academic Press.

Journal Article↗
PubMed1980

Limited gallium scans and angiotensin converting enzyme in granulomatous uveitis.

The use of serum angiotensin converting enzyme (ACE) and limited gallium scans of the head, neck, and chest for patients with granulomatous uveitis is described. Mean serum ACE activity was elevated in patients with granulomatous uveitis regardless of the presence of systemic sarcoidosis. Furthermore, pathologic gallium uptake was noted in lacrimal glands, parotid glands, and lungs in some cases. These results indicate that sarcoidosis may be more common than previously believed in these patients.

Adult↗
PubMed2004

Gallium nitride-based potentiometric anion sensor.

The gallium nitride (GaN) semiconductor is used as the sensing element for the development of a potentiometric anion sensor. The anion recognition mechanism is based on the selective interaction of anions in solution with the epitaxial Ga-face polarity GaN (0001) wurtzite crystal film grown on sapphire. The native GaN crystal is used for the development of an ion blocked sensor. The potential is based on the Volta potential, generated at the semiconductor/solution interface and within the Helmholtz layer, due to specifically adsorbed anions. The selectivity of the sensor is based on the direct interaction of the anionic ligand with the outer electron-defective gallium atoms; thus, it is not dependent on the lipophilicity of the adsorbed charged species. The chemical resistivity of the GaN crystal provides sensors with excellent lifetime, signal stability, and reproducibility.

Journal Article↗
PubMed2001

Electron transfer. 147. Reductions with gallium(I).

Solutions 0.03-0.05 M in gallium(I) can be generated by treatment of the "mixed" halide Ga(I)Ga(III)Cl(4) with cold water under argon and then removing the precipitated metallic gallium and Ga(OH)(3) by centrifugation. Ga(I) is lost from such preparations with a half-life of about 3 h at 0 degrees C. These solutions, which may be handled by conventional techniques, readily reduce I(3)(-), IrCl(6)(2)(-), Fe(bipy)(3)(3+), Fe(NCS)(2+), aquacob(III)alamin, and a group of ring-substituted derivatives of Ru(NH(3))(5)(py)(3+) but are inert to (NH(3))(5)CoCl(2+) and (NH(3))(5)CoBr(2+). All reactions give Ga(III). Reduction of HCrO(4)(-) in 2-ethyl-2-hydroxybutanoate buffers (pH 3.6) yields a Cr(IV) chelate of the buffering anion but forms Cr(III) when carried out in 0.01 M H(+). Reactions of le(-) oxidants proceed via successive single changes with the conversion Ga(II) --> Ga(III) much more rapid than Ga(I) --> Ga(II). Only for the reactions of I(3)(-) and Fe(NCS)(2+) is there evidence for redox bridging.

Journal Article↗
PubMed2001

Formation of gallium dimers in the intermetallic compounds R(5)Ga(3) (R = Sc, Y, Ho, Er, Tm, Lu). Deformation of the Mn(5)Si(3)-type structure.

The R(5)Ga(3) (R = Sc, Y, Ho, Er, Tm, Lu) phases were prepared by high-temperature solid-state techniques. The structure of monoclinic Sc(5)Ga(3) was determined by single-crystal X-ray diffraction means (C2/m, No. 12, Z = 4, a = 8.0793(5) A, b = 14.003(1) A, c = 5.9297(3) A, beta = 90.994(5) degrees ), and those of the isotypic R(5)Ga(3), R = Y, Ho, Er, Tm, Lu, were determined by Guinier powder diffraction. The new Sc(5)Ga(3) structure is a deformation of the hexagonal Mn(5)Si(3) type (P6(3)/mcm) and contains two types of gallium dimers with d(Ga-Ga) = 2.91 and 3.14 A. The closely spaced Sc1 chains in the parent Mn(5)Si(3) type transform to zigzag chains in concert with displacements of the uniformly spaced gallium atoms to form dimers within distorted confacial square antiprisms of Sc. Matrix effects appear important in the different Ga(2) bond lengths. Electronic calculations reveal that the transformation from the hypothetical Mn(5)Si(3) to the Sc(5)Ga(3) type is aided by antibonding Ga-Ga interactions between the dimers that are pushed above E(F) and Ga-Ga and Ga-Sc bonding states just below E(F) that are stabilized. Sc(5)Ga(3) is appropriately metallic. Except for R = Sc, Lu, the arc-melted R(5)Ga(3) compounds above slowly transform on annealing at 1150 degrees C and below into tetragonal Ba(5)Si(3)-type structures.

Journal Article↗