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PubMed1987

Quantitative gallium 67 lung scan to assess the inflammatory activity in the pneumoconioses.

Gallium 67 lung scan has recently become increasingly used to evaluate the biological activity of alveolitis of interstitial lung diseases and to stage the disease process. In order to have a more precise and objective indicator of the inflammatory activity in the lung, we and others have developed computer-based quantitative techniques to process the 67Ga scan. In this report, we compare the results of three such computer-based methods of analysis of the scans of 38 normal humans and 60 patients suspected to have pneumoconiosis. Results of previous investigations on the mechanisms of 67Ga uptake in interstitial lung disease are reviewed. These data strengthen the view that quantitative 67Ga lung scan has become a standard technique to assess inflammatory activity in the interstitial lung diseases and that computer-based method of analysis of the scan provides an index of inflammatory activity of the lung disease that correlates with lung lavage and biopsy indices of inflammation in the lung tissue.

Asbestosis↗

PubMed1996

Abdominal abscess detection: gallium, 111In-, and 99mTc-labeled leukocytes, and polyclonal and monoclonal antibodies.

Computed tomography (CT) and magnetic resonance imaging (MRI) are excellent modalities for imaging patients with localizing signs of an intra-abdominal abscess. However, radionuclide techniques have an advantage over CT and MRI because they can evaluate the entire body for infection. In addition, radionuclides can noninvasively differentiate infection and inflammation from benign fluid collections. Radiopharmaceuticals available for imaging abdominal infection include gallium-67 citrate, indium-111, and technetium-99m-labeled leukocytes, and radiolabeled whole antibodies. The use of these radiopharmaceuticals for abdominal imaging is dependent on their biodistribution and mechanism of abscess localization.

Abdominal Abscess↗

PubMed1997

The continuing clinical role of gallium 67 scintigraphy in the age of receptor imaging.

Gallium 67 scintigraphy is useful clinically for assessment of tumor viability after treatment of Hodgkin's and nonHodgkin's lymphoma. Because more than 50% of the patients with complete response have a residual mass after treatment, computed tomography is not a good test to determine if a patient has reached a complete response. 67Ga scintigraphy, on the other hand, has a sensitivity of 76% to 100% and specificity of 75% to 96% to determine if a residual mass is a residual cancer or made up only of fibrosis and necrosis. Early diagnosis of recurrence is important in order to start therapy when the tumor can, potentially, still be controlled. The sensitivity of 67Ga for diagnosis of recurrence is 95% and the specificity 89%. Scintigraphy has been shown to diagnose recurrence sometimes months before other tests. 67Ga scintigraphy also has the potential to separate rapid from slow responders during therapy. Even when it has been known for many years, 67Ga has proved recently to be a useful test in assessing lymphoma patients after treatment.

Adult↗

PubMed1983

Gallium scanning in the diagnosis of hepatocellular carcinoma: a clinicopathological study of 45 patients.

Gallium-67 citrate scintigraphy was carried out in 45 patients with primary hepatocellular carcinoma in conjunction with serum alpha-fetoprotein measurement, 99mTc-colloid liver scan and selective arteriography. 67Ga accumulated in the tumour in 31 patients, and partial uptake was noted in three others. Scanning detected small hepatomas in four patients with cirrhosis in whom 99mTc-colloid scanning was negative. Clinical, laboratory and histopathological comparisons of 67Ga-positive and -negative patients showed no significant differences. 67Ga scanning of the liver was found to be useful in the diagnosis of hepatocellular carcinoma, especially in patients with associated cirrhosis.

Adult↗

PubMed1979

Gallium-67 scanning and conservative treatment in acute inflammatory lesions of the renal cortex.

Three cases of suspected acute suppurative lesions of the renal cortex treated successfully with antimicrobial agents are presented. In support of other reports it appears that selected cases, particularly when diagnosed early, may be managed conservatively without surgical drainage. In those cases of severe sepsis, large intrarenal or perinephric abscesses, resistant organisms or those that are refractory to treatment, surgical intervention may be unavoidable. Gallium-67 nuclear scanning is a safe, non-invasive method of locating rapidly these areas of inflammation and has proved to be a useful tool in earlier diagnosis.

Adolescent↗

PubMed1978

Gallium-67 scintigraphy in the diagnosis of renal cortical abscess.

Clinical and radiologic diagnosis of a renal cortical abscess is difficult. A plain x-ray of the kidneys, ureters and bladder, an excretory urogram with nephrotomography, nephrosonography and renal angiography may not be helpful in the diagnosis. A case is presented of bilateral polycystic kidneys with a renal cortical abscess of the lower pole of the left kidney. An abscess could not be localized by the routine radiologic procedures. Gallium-67 scintigraphy demonstrated a renal cortical abscess of the left kidney, which was treated successfully by operation.

Abscess↗

PubMed2003

Impact of in vitro gallium arsenide exposure on macrophages.

The semiconductor gallium arsenide (GaAs) is classified as an immunotoxicant and a carcinogen. We previously showed that GaAs in vivo induces several phenotypic changes in macrophages located at the exposure site, indicative of an activated state. These physiological alterations may be a primary or secondary consequence of chemical exposure. To discern primary influences, our current study examined the in vitro effects of the chemical on macrophage cell lines and murine peritoneal macrophages. GaAs augmented cathepsins L and B proteolytic activities in all three sources of macrophages. Expression of the two mature isoforms of invariant chain and its cleavage fragment was also significantly increased, indicating that the chemical directly affects macrophages. However, GaAs did not alter the overall cell surface expression of major histocompatibility complex class II molecules on macrophages nor influence their ability to stimulate antigen-specific helper T cell hybridomas to respond to intact antigens that require processing. These findings raise the possibility that the chemical's complete in vivo impact may involve cytokines. Further, GaAs in vitro enhanced steady-state cathepsin L protein, and cathepsins L and B mRNA expression in macrophages, indicating that GaAs may alter gene expression, which may contribute to the chemical's adverse biological effects.

Animals↗

PubMed1995

The value of combined serum angiotensin-converting enzyme and gallium scan in diagnosing ocular sarcoidosis.

PURPOSE: To evaluate the role of combined serum angiotensin-converting enzyme (ACE) activity and whole-body gallium (67GA) scanning in diagnosing sarcoidosis in patients with features consistent with ocular sarcoidosis but with normal or equivocal chest radiographs. METHODS: Serum ACE levels and whole-body 67GA scans were obtained as part of the initial workup in 22 patients with active ocular inflammation and ultimately biopsy-proven sarcoidosis (sarcoid uveitis group). A second group consisting of 70 patients with active uveitis in whom sarcoidosis also was considered a diagnostic possibility also was studied. All 70 patients ultimately had a definitive diagnosis other than sarcoidosis (nonsarcoid uveitis). All patients in this group also had a serum ACE and whole-body 67GA scan performed as part of their initial investigations. RESULTS: All patients in the sarcoid uveitis group had either an elevated ACE level or an abnormal scan. In 16 of the 22 patients, results of both tests were abnormal. In no patient in the nonsarcoid uveitis group were results of both tests abnormal. The sensitivity of an elevated ACE in diagnosing sarcoidosis was 73% and the specificity was 83%. Using the combination of a positive 67GA scan and an elevated ACE, the specificity for diagnosis was 100% and the sensitivity was 73%. CONCLUSIONS: The combination of serum ACE level and whole-body 67GA scan increases the diagnostic specificity without affecting sensitivity in patients with clinically suspicious ocular sarcoidosis who have normal or equivocal chest radiographs.

Adolescent↗

PubMed1997

Synthesis and structural characterization of mixed aluminum-gallium-offretites.

A new synthesis procedure is reported for the preparation of mixed Al,Ga-offretites over the entire solid solution range 0 < or = Ga/(Ga + Al) < or = 1. The resulting materials are characterized by X-ray powder diffraction, adsorption microcalorimetry and multinuclear solid state NMR. The 29Si MAS-NMR data are consistent with statistical occupancy of the T1 and T2 sites by aluminum and gallium, and also show no positive evidence for preferential siting effects between both framework metals. Isotropic chemical shifts and nuclear electric quadrupolar coupling constants for 27Al and 71Ga have been obtained from a field-dependent analysis of the center of gravity in the MAS-NMR spectra. H-Al,Ga-offretites produced by ammonium exchange and subsequent calcination reveal evidence of partial demetallation of the framework with formation of extra-lattice metal species.

Aluminum↗

PubMed1999

Evaluation of gallium-68 tris(2-mercaptobenzyl)amine: a complex with brain and myocardial uptake.

Previous research into development of a gallium-radiolabeled agent that crosses the blood-brain barrier has met with limited success. In this study, we focused our attention on a Ga(III) complex of a 4-coordinate amine trithiolate tripod ligand, tris(2-mercaptobenzyl) amine (S3N). The Ga(III) S3N complex is small, neutral, and lipophilic, meeting the requirements for a potential brain imaging agent. The Ga-68 complex was easily formed with a radiochemical purity of >95%. In vitro stability of the Ga-S3N complex, determined in rat serum incubated at 37 degrees C, was greater than 95% intact at 2 h by silica gel and reversed-phase radio-thin layer chromatography. Biodistribution studies conducted in female Sprague-Dawley rats showed the complex cleared rapidly from the blood with initial high liver uptake followed by rapid washout. Significant uptake was observed in the brain, with brain:blood ratios increasing from 0.11 at 2 min postinjection to 3.8 at 60 min postinjection. Uptake was also observed in the heart going from a heart:blood ratio of 2.3 at 2 min postinjection to 11 at 60 min postinjection. Molecular mechanics were used to determine the coordination number, and demonstrated that the Ga(III) complex prefers to be 4-coordinate. Imaging studies with 68Ga-S3N in a Nemestrina macaque showed significant brain uptake, similar to other lipophilic agents. The extraction of 68Ga-S3N into the brains of both rodents and primates, higher than any 68Ga agent reported in the literature, suggests that this compound may have potential as a brain imaging agent for positron emission tomography.

Animals↗

PubMed2002

Gallium in cancer treatment.

Gallium (Ga) is the second metal ion, after platinum, to be used in cancer treatment. Its activities are numerous and various. It modifies three-dimensional structure of DNA and inhibits its synthesis, modulates protein synthesis, inhibits the activity of a number of enzymes, such as ATPases, DNA polymerases, ribonucleotide reductase and tyrosine-specific protein phosphatase. Ga alters plasma membrane permeability and mitochondrial functions. Ga salts are taken up more efficiently and more specifically by tumour cells when orally administered. New compounds have been prepared: Ga maltolate, doxorubicin-Ga-transferrin conjugate and Tris(8-quinolinolato)Ga(III), which show interesting activities. Ga toxicity is well documented in vitro and in vivo in animals. In humans, the oral administration Ga is less toxic, and allows a chronic treatment, allowing an improvement of its bioavailability in tumours, by comparison with the parenteral use. The anticancer activity of Ga salts has been demonstrated but other effects have also been noted such as many bone effects that could be useful in bone metastatic patients. Its has also been shown that a long period of administration could induce tumour fibrosis. Ga is synergistic with other anticancer drugs. Although not as potent as platinum in vitro, the anticancer activity of Ga should not be ignored, but the schedule of administration still needs to be optimised and new compounds are now under clinical investigations.

Animals↗

PubMed1996

Effects of an erbium, chromium: yttrium, scandium, gallium, garnet laser on mucocutanous soft tissues.

OBJECTIVES: Lasers are effective tools for soft tissue surgery. The erbium, chromium: yttrium, scandium, gallium, garnet laser is a new system that incorporates an air-water spray. This study evaluates the cutting margins of this laser and compares healing with laser and conventional scalpel and punch biopsy-induced wounds. STUDY DESIGN: New Zealand white rabbits were divided into serial sacrifice groups; the tissues were grossly and microscopically analyzed after laser and convential steel surgical wounding. RESULTS: Wound margins were found to show minimal edge coagulation artifact and were 20 to 40 mm in width. Laser wounds showed minimal to no hemorrhage and re-epithelialization and collagenization were found to occur by day 7 in both laser and conventional groups. CONCLUSIONS: The new laser system is an effective soft tissue surgical device; wound healing is comparable to that associated with surgical steel wounds. The minimal edge artifact observed with this laser system should allow for the procurement of diagnostic biopsy specimens.

Aluminum Silicates↗

PubMed2003

Gallium arsenide exposure impairs splenic B cell accessory function.

Gallium arsenide (GaAs) is utilized in industries for its semiconductor and optical properties. Chemical exposure of animals systemically suppresses several immune functions. The ability of splenic B cells to activate antigen-specific helper CD4(+) T cell hybridomas was assessed, and various aspects of antigen-presenting cell function were examined. GaAs-exposed murine B cells were impaired in processing intact soluble protein antigens, and the defect was antigen dependent. In contrast, B cells after exposure competently presented peptides to the T cells, which do not require processing. Cell surface expression of major histocompatibility complex (MHC) class II molecules and several costimulatory molecules on splenic B cells, which are critical for helper T cell activation, was not affected by chemical exposure. GaAs exposure also did not influence the stability of MHC class II heterodimers, suggesting that the defect may precede peptide exchange. GaAs-exposed B cells contained a normal level of aspartyl cathepsin activity; however, proteolytic activities of thiol cathepsins B and L were approximately half the control levels. Furthermore, two cleavage fragments of invariant chain, a molecular chaperone of MHC class II molecules, were increased in GaAs-exposed B cells, indicative of defective degradation. Thus, diminished thiol proteolytic activity in B cells may be responsible for their impaired antigen processing and invariant chain degradation, which may contribute to systemic immunosuppression caused by GaAs exposure.

Animals↗

PubMed1986

Exchange of iron by gallium in siderophores.

Siderophores are iron transport compounds produced by numerous microorganisms and which strongly chelate Fe(III), but not Fe(II). Other trivalent metals, such as Al(III), Cr(III), or Ga(III), are not capable of significantly displacing iron from siderophores. However, I demonstrate here that Ga(III) can effectively displace iron under reducing conditions. With ascorbate as reductant and ferrozine as Fe(II) trapping agent, the kinetics of reductive displacement of iron by Ga(III) were followed spectroscopically by the increase of absorbance at 562 nm due to formation of the Fe(II)-ferrozine complex. No significant reduction of siderophore occurred in the absence of Ga(III). With excess Ga(III), the displacement was quantitative and very rapid. The rate of metal exchange was pseudo first order with respect to Ga(III) concentration and highly pH dependent, suggesting that siderophore ligands are displaced from the iron in a concerted mechanism by Ga(III) and protonation to expose the Fe(III) to reduction by ascorbate. Reaction rates were dependent upon the structure of the siderophore, being greatest for ferric rhodotorulic acid and slowest for ferrichrome A at pH 5.4. The pH profile for ferric rhodotorulic acid was unusual in that it showed a maximum at pH 6.5, while all other siderophores examined showed an increase in rate as pH was lowered from 7.0. The physiological significance of this reaction to the clinical use of gallium is discussed.

Gallium↗

PubMed2006

Synthesis, characterization, and electrochemical studies on [1.1]ferrocenophanes containing aluminum, gallium, and indium.

The synthesis, characterization, structure, and electrochemistry of [1.1]ferrocenophanes, bridged by the heavier group 13 elements aluminum (1a), gallium (1b), and indium (1c), are described and discussed. Compounds 1a-c have been synthesized from dilithioferrocene and intramolecularly coordinated group 13 element dihalides Ar'EX(2) (Ar' = 2-(Me(2)NCH(2))C(6)H(4); EX(2) = AlCl(2), GaCl(2), InI(2)). Although the synthesis and characterization of 1a by single-crystal X-ray analysis has been described recently (Braunschweig, H.; Burschka, C.; Clentsmith, G. K. B.; Kupfer, T.; Radacki, K. Inorg. Chem. 2005, 44, 4906), compounds 1b and 1c are described for the first time. The galla (1b) and the inda (1c) [1.1]ferrocenophane have been characterized by single-crystal X-ray determination [1b: C(38)H(40)Fe(2)Ga(2)N(2), monoclinic, P2(1)/c, a = 10.3467(5) Angstroms, b = 11.6311(4) Angstroms, c = 14.0747(7) Angstroms, beta = 105.931(2) degrees, Z = 2; 1c: C(38)H(40)Fe(2)In(2)N(2), monoclinic, P2(1)/c, a = 10.5522(7) Angstroms, b = 11.8476(8) Angstroms, c = 13.9855(9) Angstroms, beta = 104.990(3) degrees, Z = 2]. All three compounds 1a-c are anti conformers with trans orientations of the two donating NMe(2) groups. For the [1.1]ferrocenophane 1a, an unprecedented fully reversible two-electron redox process was observed by cyclic voltammetry, whereas the corresponding Ga and In species exhibit a more conventional stepwise redox chemistry. According to the Robin-Day classification, 1a is a class I and 1b and 1c are class II species. In addition to the reversible processes, compound 1a shows an irreversible oxidation at higher voltages accompanied by adsorption processes. The irreversible adsorption process was investigated with an electrochemical quartz crystal microbalance (EQCM).

Aluminum↗

PubMed2006

Synthesis, structure, and anticancer activity of gallium(III) complexes with asymmetric tridentate ligands: growth inhibition and apoptosis induction of cisplatin-resistant neuroblastoma cells.

Five gallium(III) complexes described as [Ga(III)(LX)2]ClO4, where (LX)- is the deprotonated form of a series of asymmetric ligands containing pyridine and 4,6-substituted phenol moieties, were synthesized and characterized by spectroscopic and spectrometric methods. Phenol substituents encompass the electron-withdrawing and electron-donating methoxy (1), nitro (2), chloro (3), bromo (4), and iodo (5) groups. Complexes 1 and 3 have had their molecular structure solved by X-ray crystallography and show distinct coordination modes. Complexes 1-5 were tested for growth-inhibition activity on cisplatin-resistant human neuroblastoma cells; those containing halogen substituents on the phenolate rings, i.e., 3-5, showed activity superior to that observed for cisplatin and induced apoptosis of neuroblastoma cells. Nitro-containing 2 suppressed proliferation of the neuroblastoma cells but induced apoptosis less effectively.

Antineoplastic Agents↗

PubMed2001

Phenylthiyl radical complexes of gallium(III), iron(III), and cobalt(III) and comparison with their phenoxyl analogues.

Three hexadentate, asymmetric pendent arm macrocycles containing a 1,4,7-triazacyclononane-1,4-diacetate backbone and a third, N-bound phenolate or thiophenolate arm have been synthesized. In [L(1)](3)(-) the third arm is 3,5-di-tert-butyl-2-hydroxybenzyl, in [L(2)](3)(-) it is 2-mercaptobenzyl, and in [L(3)](3)(-) it is 3,5-di-tert-butyl-2-mercaptobenzyl. With trivalent metal ions these ligands form very stable neutral mononuclear complexes [M(III)L(1)] (M = Ga, Fe, Co), [M(III)L(2)] (M = Ga, Fe, Co), and [M(III)L(3)] (M = Ga, Co) where the gallium and cobalt complexes possess an S = 0 and the iron complexes an S = (5)/(2) ground state. Complexes [CoL(1)].CH(3)OH.1.5H(2)O, [CoL(3)].1.17H(2)O, [FeL(1)].H(2)O, and [FeL(2)] have been characterized by X-ray crystallography. Cyclic voltammetry shows that all three [M(III)L(1)] complexes undergo a reversible, ligand-based, one-electron oxidation generating the monocations [M(III)L(1)(*)](+) which contain a coordinated phenoxyl radical as was unambiguously established by their electronic absorption, EPR, and Mössbauer spectra. In contrast, [M(III)L(2)] complexes in CH(3)CN solution undergo an irreversible one-electron oxidation where the putative thiyl radical monocationic intermediates dimerize with S-S bond formation yielding dinuclear disulfide species [M(III)L(2)-L(2)M(III)](2+). [GaL(3)] behaves similarly despite the steric bulk of two tertiary butyl groups at the 3,5-positions of the thiophenolate, but [Co(III)L(3)] in CH(2)Cl(2) at -20 to -61 degrees C displays a reversible one-electron oxidation yielding a relatively stable monocation [Co(III)L(3)(*)](+). Its electronic spectrum displays intense transitions in the visible at 509 nm (epsilon = 2.6 x 10(3) M(-)(1) cm(-)(1)) and 670sh, 784 (1.03 x 10(3)) typical of a phenylthiyl radical. The EPR spectrum of this species at 90 K proves the thiyl radical to be coordinated to a diamagnetic cobalt(III) ion (g(iso) = 2.0226; A(iso)((59)Co) = 10.7 G).

Cobalt↗

PubMed2006

Photochemical functionalization of gallium nitride thin films with molecular and biomolecular layers.

We demonstrate that photochemical functionalization can be used to functionalize and photopattern the surface of gallium nitride crystalline thin films with well-defined molecular and biomolecular layers. GaN(0001) surfaces exposed to a hydrogen plasma will react with organic molecules bearing an alkene (C=C) group when illuminated with 254 nm light. Using a bifunctional molecule with an alkene group at one end and a protected amine group at the other, this process can be used to link the alkene group to the surface, leaving the protected amine exposed. Using a simple contact mask, we demonstrate the ability to directly pattern the spatial distribution of these protected amine groups on the surface with a lateral resolution of <12 mum. After deprotection of the amines, single-stranded DNA oligonucleotides were linked to the surface using a bifunctional cross-linker. Measurements using fluorescently labeled complementary and noncomplementary sequences show that the DNA-modified GaN surfaces exhibit excellent selectivity, while repeated cycles of hybridization and denaturation in urea show good stability. These results demonstrate that photochemical functionalization can be used as an attractive starting point for interfacing molecular and biomolecular systems with GaN and other compound semiconductors.

Acetamides↗