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PubMed1992

Dissimilar aluminum and gallium permeation of the blood-brain barrier demonstrated by in vivo microdialysis.

Aluminum (Al) and gallium (Ga) permeations of the blood-brain barrier (BBB) were assessed in rats. Unbound extracellular Al and Ga concentrations were ascertained at the two potential sites of BBB permeation, cerebral capillaries and choroid plexuses, by implantation of microdialysis probes in the frontal cortex and lateral ventricle, respectively. A microdialysis probe implanted in the jugular vein revealed unbound blood Al or Ga concentrations. Al or 67Ga citrate was administered via the femoral vein. Peak Al and Ga concentrations were seen within the first 10 min at all three sites. Area under the curve (concentration vs. time to final sample) values were calculated using RSTRIP. Within-rat overall frontal cortical/blood and lateral ventricular/blood ratios [brain/blood ratios (oBBRs)] were calculated from area under the curve values. Aluminum frontal cortical oBBRs were significantly higher than those for the lateral ventricle. Ga oBBRs were not significantly different between the two sites. Al and Ga oBBRs were significantly different in the lateral ventricle. These results suggest that the primary site of A1 permeation across the BBB is at cerebral capillaries, whereas Ga permeation across the BBB does not significantly differ between cerebral capillaries and choroid plexuses. The use of Ga as a model to study Al pharmacokinetics may not be appropriate in the elucidation of the site or mechanism of Al entry into the brain.

Aluminum↗
PubMed1994

Gallium chloride effects on neonatal rat heart cells in culture, in standard and oxidative conditions.

The effects of gallium chloride (GaCl3) at 7.17, 28.68 and 114.7 microns (0.5, 2 and 8 mg/l of Ga3+) were checked in cardiac cells derived from 2-4 day-old newborn rats, cultured for 72 h in Eagle's minimum essential medium (MEM), enriched with 10% foetal calf serum (v/v) and 2 mM of glutamine at 37 degrees C, with 95% air plus 5% CO2. After 3 hours of standard culture conditions (MEM with glucose 5 mM), Ga treatment induced an increase of glycogen stores without any influence on ATP, ADP, and AMP concentrations. A slight and transient decrease in the beat rate was noted after 15 min of exposure to GaCl3 at all concentrations, whereas there was no difference in the beat rate nor in the cell contraction amplitude after 3 hours of exposure. After 1.5 h in conditions of oxidation (Tyrode solution without glucose, FeCl2 20 microM, ascorbic acid 0.2 mM), GaCl3 at 8 mg/l decreased the malondialdehyde (MDA) production as assessed by the decrease of intracellular concentrations and the decrease of its release in the supernatant. The decreased MDA production following oxidative stress, the increase in glycogen stores in normal oxygen concentrations, as well as the maintenance of ATP concentrations and the lack of any chronotropic effect induced by GaCl3 suggests a protective rather than a deleterious cardiac effect.

Animals↗
PubMed2006

Comparison of (11)C-acetate positron emission tomography and (67)Gallium citrate scintigraphy in patients with hepatocellular carcinoma.

AIMS: Nuclear imaging may have an increasing role in the diagnosis of hepatocellular carcinoma (HCC). The aim of this study was to compare prospectively the Gallium-67 citrate ((67)Ga) scintigraphy results with those obtained by positron emission tomography (PET) using (11)C-acetate in patients with HCC. METHODS: We prospectively analysed 21 patients (mean age, 64+/-11 years) with histopathologically verified HCC undergoing (11)C-acetate PET and (67)Ga scintigraphy. (67)Ga scans were not performed in three of these 21 patients due to the exacerbation of the disease. Whole-body (11)C-acetate PET were performed following intravenous injection of 850 MBq of (11)C-acetate. For (67)Ga scintigraphy, whole-body, planar and single photon emission computed tomography imaging acquisitions were performed after intravenous application of a mean dose of 189 MBq (67)Ga. RESULTS: (67)Ga scintigraphy found abnormalities only in 10 of 18 patients (56%) and detected 22 of 46 clinically involved sites (48%); it was false-positive in two patients. (11)C-acetate PET found abnormalities in 14 of 18 patients (78%) and detected 36 of 46 clinical lesions (78%); it was false-positive in one patients. In one patient with left supraclavicular lymph node metastases, neither the (67)Ga scintigraphy nor the conventional computed tomography have shown the lesions, which were clearly demonstrated by the (11)C-acetate PET. CONCLUSION: Our results indicate significantly higher sensitivity and specificity of (11)C-acetate PET than (67)Ga scan in detection of HCC lesions. This study suggests that imaging with (11)C-acetate PET might play a potential role in the diagnostic workup of patients with HCC.

Aged↗
PubMed1988

Postoperative infection with the automatic implantable cardioverter defibrillator: clinical presentation and use of the gallium scan in diagnosis.

This report describes three patients with infection involving an automatic implantable cardioverter defibrillator. All three patients presented with fever, fluid in the pulse generator pocket, leukocytosis and an elevated erythrocyte sedimentation rate. A gallium scan, together with aspiration and culture of the fluid from the pocket, confirmed the diagnosis in each case.

Candidiasis↗
PubMed2003

Gallium arsenide selectively up-regulates inflammatory cytokine expression at exposure site.

Gallium arsenide (GaAs), a technologically and economically important semiconductor, is widely utilized in both military and commercial applications. This chemical is a potential health hazard as a carcinogen and immunotoxicant. We previously reported that macrophages at the exposure site exhibit characteristics of activation. In vitro culture of macrophages with GaAs fails to recapitulate the in vivo phenotype, suggesting that complete GaAs-mediated activation in vivo may require other cells or components found in the body's microenvironment. Our present study examined the role of cytokines upon GaAs-mediated macrophage activation. Intraperitoneal administration of GaAs elicited rapid specific recruitment of blood monocytes to the exposure site. This recruitment occurred concomitant with up-regulation of 17 chemokine and inflammatory cytokine mRNAs, while transcripts of three inhibitory cytokines diminished. Administration of latex beads caused less cytokine induction than GaAs, indicating that changes in mRNA levels could not be attributed to phagocytosis. Four representative chemokines and cytokines were selected for further analysis. Increased cytokine mRNA expression was paralleled by similar increases in cytokine protein levels, and secreted protein products were detected in peritoneal fluid. Cytokine protein expression was constrained to myeloid cells, and to a lesser extent to B cells. Alterations in patterns of cytokine gene expression elucidate mechanisms for increased cellular activation and antigen processing, and modulation of the inflammatory response. Our findings indicate that in vivo GaAs exposure alters cytokine gene expression, which may lead to an inflammatory reaction and contribute to pathological tissue damage.

Animals↗
PubMed1995

Electronic states in gallium arsenide quantum wells probed by optically pumped NMR.

An optical pumping technique was used to enhance and localize nuclear magnetic resonance (NMR) signals from an n-doped GaAs/Al0.1Ga0.9As multiple quantum well structure, permitting direct radio-frequency measurements of gallium-71 NMR spectra and nuclear spin-lattice relaxation rates (1/T1) as functions of temperature (1.6 K < T < 4.2 K) and the Landau level filling factor (0.66 < v < 1.76). The measurements reveal effects of electron-electron interactions on the energy levels and spin states of the two-dimensional electron system confined in the GaAs wells. Minima in 1/T1 at v approximately 1 and v approximately 2/3 indicate energy gaps for electronic excitations in both integer and fractional quantum Hall states. Rapid, temperature-independent relaxation at intermediate v values indicates a manifold of low-lying electronic states with mixed spin polarizations.

Arsenicals↗
PubMed1997

Cytotoxic analogs of the iron(III) chelator pyridoxal isonicotinoyl hydrazone: effects of complexation with copper(II), gallium(III), and iron (III) on their antiproliferative activities.

This study examined if complexation with metals increased the antiproliferative activities of chelators of the pyridoxal isonicotinoyl hydrazone (PIH) class. Addition of iron(III) to some PIH analogs markedly depressed their activities, whereas it had little effect on others. The gallium(III) complex of PIH, but not its copper(II) complex, was more efficient than the apochelator at inhibiting [3H]thymidine incorporation.

Antineoplastic Agents↗
PubMed2000

Gallium disrupts iron metabolism of mycobacteria residing within human macrophages.

Mycobacterium tuberculosis and M. avium complex (MAC) enter and multiply within monocytes and macrophages in phagosomes. In vitro growth studies using standard culture media indicate that siderophore-mediated iron (Fe) acquisition plays a critical role in the growth and metabolism of both M. tuberculosis and MAC. However, the applicability of such studies to conditions within the macrophage phagosome is unclear, due in part to the absence of experimental means to inhibit such a process. Based on the ability of gallium (Ga(3+)) to concentrate within mononuclear phagocytes and on evidence that Ga disrupts cellular Fe-dependent metabolic pathways by substituting for Fe(3+) and failing to undergo redox cycling, we hypothesized that Ga could disrupt Fe acquisition and Fe-dependent metabolic pathways of mycobacteria. We find that Ga(NO(3))(3) and Ga-transferrin produce an Fe-reversible concentration-dependent growth inhibition of M. tuberculosis strains and MAC grown extracellularly and within human macrophages. Ga is bactericidal for M. tuberculosis growing extracellularly and within macrophages. Finally, we provide evidence that exogenously added Fe is acquired by intraphagosomal M. tuberculosis and that Ga inhibits this Fe acquisition. Thus, Ga(NO(3))(3) disruption of mycobacterial Fe metabolism may serve as an experimental means to study the mechanism of Fe acquisition by intracellular mycobacteria and the role of Fe in intracellular survival. Furthermore, given the inability of biological systems to discriminate between Ga and Fe, this approach could have broad applicability to the study of Fe metabolism of other intracellular pathogens.

Cells, Cultured↗
PubMed2003

Gallium-67 SPECT scintigraphy may be useful in diagnosis of temporal arteritis.

BACKGROUND: Temporal arteritis (TA) is a common syndrome in the elderly, consisting of persistent pain in the temporal area of the skull, jaw claudication, sudden visual loss, high erythrocyte sedimentation rate, and tenderness on palpation in the temporal area. The diagnosis of this condition is relatively straightforward when the typical symptoms and a positive temporal artery biopsy are present. However, only half of the patients have a positive temporal artery biopsy. Other diagnostic procedures, such as colour Doppler sonography or superficial carotid artery angiography which have been proved to be useful for the diagnosis of TA, do not discriminate between inflammatory and non-inflammatory temporal artery disease and may be helpful only in experienced hands. Gallium-67 ((67)Ga) planar scan was reported to be useful in the diagnosis of the disease. Quantitative (67)Ga single photon emission computed tomography (SPECT) may raise the accuracy of the diagnosis. OBJECTIVE: To investigate the effectiveness and usefulness of (67)Ga SPECT scintigraphy in the diagnosis of TA. METHODS: Nine patients (five male, four female) and six controls were included in the study. All of them received 8-10 mCi (67)Ga intravenously 48 hours before the scan.(67)Ga uptake ratios were calculated on transaxial and coronal slices. RESULTS: All patients showed increased uptake in the temporal area of the skull compared with controls. CONCLUSION: The data suggest that (67)Ga skull SPECT may be useful in the diagnosis of TA, especially if the uptake ratio in the area of interest is calculated. Further studies are needed to confirm these data.

Aged↗
PubMed1982

Lung inflammation in sarcoidosis: comparison of serum angiotensin-converting enzyme levels with bronchoalveolar lavage and gallium-67 scanning assessment of the T lymphocyte alveolitis.

Serum angiotensin-converting enzyme (ACE) is elevated in many patients with pulmonary sarcoidosis and has been proposed as a measure of disease activity. The present study was designed to evaluate the possible relationship between serum ACE and direct measures of the intensity of the alveolitis of pulmonary sarcoidosis as measured by bronchoalveolar lavage and gallium-67 (67Ga) scans. To accomplish this, 64 measurements of serum ACE, lavage T lymphocytes, and lung uptake of 67Ga were performed in 41 patients with biopsy-proven sarcoidosis. Elevations of serum ACE were found on at least one occasion in 17 patients (41%). However, serum ACE was found to be a poor predictor of the intensity of alveolitis in sarcoidosis as assessed by the quantitation of bronchoalveolar lavage cells that were T lymphocytes and by 67Ga scanning. Elevated serum ACE did not predict which patients would have elevated proportions of lavage T lymphocytes, which patients would demonstrate increased pulmonary uptake of 67Ga, or which patients would have high-intensity alveolitis as defined by a combination of these criteria. These observations suggest that while serum ACE may be useful in diagnosing sarcoidosis, it does not reflect accurately the intensity of the alveolitis of the pulmonary component of this disease.

Adult↗
PubMed1975

Reliability of gallium brain scanning in the detection and differentiation of central nervous system lesions.

Both 99mTc-pertechnetate and 67Ga-citrate brain scans were performed in 93 patients with cerebral neoplasms and in 70 others with cerebral infarction or hemorrhage. Tumor detection was clearly better with 67Ga(96%) than with 99mTc(85%). Cerebral infarctions consistently either failed to concentrate 67Ga(67%) of revealed a much lower concentration than the 99mTc study (27%). In 6% of the infarction patients, gallium and technetium scans were equivalent.

Arterial Occlusive Diseases↗
PubMed1976

Gallium-67 scintigraphy of pulmonary diseases as a complement to radiography.

Gallium chest scans of 575 patients were analyzed for their clinical usefulness in conjunction with chest radiographs. The series included patients with pulmonary carcinoma, lymphoma, tuberculosis, sarcoidosis, pneumoconiosis, and interstitial fibrosis. Gallum scintigraphy does not aid in the differential diagnosis of pulmonary diseases but is helpful in determining (a) the degree of activity of a known disease process: (b) treatment response, dosage, and duration; (c) the spatial extent of the disease; and (d) the presence of unsuspected disease foci hidden radiographically in the mediastinum, behind the heart, or in pleural or parenchymal scars.

Gallium Radioisotopes↗
PubMed1976

Abnormal pulmonary gallium accumulation in P. carinii pneumonia.

The potentially fatal interstitial pneumonia of Pneumocystis carinii is a frequent opportunistic invader of patients treated for malignancy with immunosuppressive and cytotoxic agents. Generalized Ga-67 pulmonary localization which is markedly disproportionate to the clinical and radiographic findings has led to earlier diagnoses by open lung biopsy in this setting. The potential usefulness of gallium scintigraphy in patients with suspected P. Carini pneumonia is presented.

Adult↗
PubMed1976

Gallium-67 myocardial imaging for the detection of bacterial endocarditis.

Eleven patients with a clinical diagnosis of bacterial endocarditis underwent scintillation scanning of the precordial region 2-7 days after the intravenous administration of 3 mCi of gallium-67 citrate. Seven had positive scans, 3 of which were confirmed by postmortem imaging at autopsy. Serial images revealed the scans to be frequently negative at 48 hours and positive from 3 to 8 days following injection. Uptake was not seen in the region of the myocardium 48 hours or longer after the injection of 15 patients without endocarditis used as controls.

Adult↗
PubMed1978

Comparison of computed tomography, ultrasonography, and gallium-67 scanning in the evaluation of suspected abdominal abscess.

A retrospective study was made of 29 consecutive patients who were evaluated for suspected abdominal abscess by at least two of three imaging modalities: gallium-67 scanning, ultrasonography, and computed tomography. No statistically significant difference in accuracy of the findings could be demonstrated. Consideration of the advantages and disadvantages of each imaging modality will often indicate which to use in an individual case. Findings from the three imaging techniques sometimes provided complementary rather than identical information.

Abdomen↗
PubMed1982

Gallium 67 citrate scanning and serum angiotensin converting enzyme levels in sarcoidosis.

Gallium 67 citrate scans and serum angiotensin converting enzyme (ACE) levels were obtained in 54 patients with sarcoidosis and analyzed in relation to clinical manifestations. 67Ga scans were abnormal in 97% of patients with clinically active disease (n = 30) and in 71% of patients with inactive disease (n = 24). Serum ACE levels were abnormally high (2 standard deviations above the control mean) in 73% of patients with clinically active disease and in 54% of patients with inactive disease. Serum ACE levels correlated significantly with 67Ga uptake score (r =.436; p less than .005). The frequency of abnormal 67Ga scans and elevated serum ACE levels suggests that inflammatory activity with little or no clinical expression is common in sarcoidosis. Abnormal 67Ga scans were highly sensitive (97%) but had poor specificity (29%) to clinical disease activity. The accuracy of negative prediction of clinical activity by normal scans (87%) was better than the accuracy of positive prediction of clinical activity by abnormal scans (63%). 67Ga scans can be used to support the clinical identification of inactive sarcoidosis.

Adult↗
PubMed1983

Radiation absorbed-dose estimates for the liver, spleen, and metaphyseal growth complexes in children undergoing gallium-67 citrate scanning.

Quantitative conjugate-view external counting techniques were applied to estimate the radiation dose to the liver, spleen, and metaphyseal growth complexes (distal femur and proximal tibia) for ten pediatric patients undergoing gallium-67 scanning procedures. The effective half-life of Ga 67 in these organs was approximately 78 hours. The dose per unit of administered activity for the liver and spleen was between 0.3 and 4.0 rad/mCi (0.08 to 1.08 Gy/GBq) and 0.5 and 7.0 rad/mCi (0.13 to 1.89 Gy/GBq), respectively. For the metaphyseal growth plates, the range was 2.3 to 14.3 rad/mCi (0.62 to 3.86 Gy/GBq).

Adolescent↗