Clinical value of gallium-67 scintigraphy in assessment of disease activity in Wegener's granulomatosis.
(41/247)
BACKGROUND: Diagnosis of active pulmonary and paranasal involvement in patients with Wegener's granulomatosis (WG) can be difficult. The diagnostic value of gallium-67 scintigraphy in WG is unclear. OBJECTIVE: To evaluate the added diagnostic value of gallium-67 scintigraphy in patients with WG with suspected granulomatous inflammation in the paranasal and chest regions. METHODS: Retrospectively, the diagnostic contribution of chest and head planar gallium scans in 40 episodes of suspected vasculitis disease activity in 28 patients with WG was evaluated. Scans were grouped into normal or increased uptake for each region. Histological proof or response to treatment was the "gold standard" for the presence of WG activity. RESULTS: WG activity was confirmed in 8 (20%) episodes, with pulmonary locations in three, paranasal in four, and both in one (n=7 patients); all these gallium scans showed increased gallium uptake (sensitivity 100%). Gallium scans were negative for the pulmonary area in 23/36 scans (specificity 64%), and negative for paranasal activity in 13/16 scans (specificity 81%) in episodes without WG activity. Positive predictive value of WG activity for lungs and paranasal region was 24% and 63%, respectively, negative predictive value was 100% for both regions. False positive findings were caused by bacterial or viral infections. CONCLUSION: Gallium scans are clinically helpful as a negative scan virtually excludes active WG. Gallium scintigraphy of chest and nasal region has a high sensitivity for the detection of disease activity in WG. However, because of positive scans in cases of bacterial or viral infections, specificity was lower. (+info)
Injury induced by chemical warfare agents: characterization and treatment of ocular tissues exposed to nitrogen mustard.
(42/247)
PURPOSE: Mustard agents are highly toxic and abundant warfare chemicals, primarily affecting ocular tissues, with no specific treatment antidote. The purpose of the present study was to examine the efficacy of novel metallocomplexes, known to inhibit the formation of highly reactive free radicals, to reduce ocular injury induced by nitrogen mustard (NM). METHODS: One eye in each of 72 rabbits was exposed to 1% to 2% NM. Topical treatment with eye drops of a metallocomplex--either zinc- or gallium-desferrioxamine (Zn/DFO and Ga/DFO)--was compared with treatment with saline, zinc (chloride), or DFO alone. Examiners masked to the treatment groups assessed the extent of ocular injury and the response to treatment using clinical, histologic, and biochemical criteria. RESULTS: Exposure to NM followed by administration of carrier alone (saline) caused severe and long-lasting injury to ocular anterior segment structures. Treatment with either Zn/DFO or Ga/DFO yielded marked protection (52%-64%), including faster healing of corneal epithelial erosions, less scarring and neovascularization, decreased inflammation in the anterior chamber, better maintenance of intraocular pressure, and less severe changes in the iris and lens. These were also associated with better preservation of systemic antioxidant status. Zinc or DFO alone afforded lower levels of protection. No toxic effects of these complexes were observed. CONCLUSIONS: It is suggested that Zn/DFO or Ga/DFO, by virtue of their enhanced ability to infiltrate cells and inhibit transition metal-dependent formation of free radicals through the combined push-pull mechanism, be considered as a basis for treatment of mustard injuries. (+info)
Hodgkin's disease. Prognostic value of Gallium-67 scintigraphy.
(43/247)
AIM: The aim of this study is to assess the clinical impact of gallium-67 scintigraphy, before and after treatment, in patients with Hodgkin's disease, and to compare the overall survival between the patients whose gallium studies after treatment were negative and those whose studies remained positive. METHODS: We have studied 75 patients (40 women, 35 men) with Hodgkin's disease. All the patients underwent (67)Ga scintigraphy at the moment of the diagnosis (basal study) and in the case that basal study was positive (abnormal hyper-uptake focus) we performed follow-up studies after the treatment. We have calculated the overall survival among patients whose studies after treatment were negative (1(st) group) and those whose studies remained positive (2(nd) group) and between patients whose studies were negative at diagnosis (3(rd) group). RESULTS: Gallium scintigraphy was positive at diagnosis in 47 patients (62.6%). In 39 of them we were able to perform the follow-up study after treatment. The follow-up study was negative in 31 patients while in 8 patients the gallium scintigraphy remained positive. The overall survival was significantly higher (p<0.001) in the 1(st) group compared with the 2(nd) group. The overall survival was higher in the 1(st) group compared with the 3(rd) but statistic significance level was not reached. CONCLUSION: Our data suggest that: 1) in Hodgkin's disease (67)Ga scintigraphy is useful to establish the diagnosis of complete remission; 2) if the gallium scan remains positive after treatment, the prognosis of patients is worse than the prognosis of patients with a negative scan. (+info)
Effects of hydrogen peroxide upon nicotinamide nucleotide metabolism in Escherichia coli: changes in enzyme levels and nicotinamide nucleotide pools and studies of the oxidation of NAD(P)H by Fe(III).
(44/247)
DNA is damaged in vivo by the Fenton reaction mediated by Fe2+ and cellular reductants such as NADH, which reduce Fe3+ to Fe2+ and allow the recycling of iron. To study the response of Escherichia coli to such cycling, the activities of several enzymes involved in nicotinamide nucleotide metabolism were measured following an H2O2 challenge. NADPH-dependent peroxidase, NADH/NADP+ transhydrogenase, and glucose-6-phosphate dehydrogenase were most strongly induced, increasing 2.5-3-fold. In addition, the cellular ratios of NADPH to NADH increased 6- or 92-fold 15 min after exposure to 0.5 or 5 mm H2O2, respectively. In vitro, NADH was oxidized by Fe3+ up to 16-fold faster than NADPH, despite their identical reduction potentials. To understand this rate difference, the interactions of Fe3+ and Ga3+ with NAD(P)H were examined by 1H, 13C, and 31P NMR spectroscopy. Association with NADH occurred primarily with adenine at N7 and the amino group, but for NADPH, strong metal interactions also occurred at the 2'-phosphate group. Interaction of M3+ (Fe3+ or Ga3+) with the adenine ring would bring it into close proximity to the redox-active nicotinamide ring in the folded form of NAD(P)H, but interaction of M3+ with the 2'-phosphate group would avoid this close contact. In addition, as determined by absorbance spectroscopy, the energy of the charge-transfer species was significantly higher for the Fe3+.NADPH complex than for the Fe3+.NADH complex. We therefore suggest that upon exposure to H2O2 the NADH pool is depleted, and NADPH, which is less reactive with Fe3+, functions as the major nicotinamide nucleotide reductant. (+info)
Gastric uptake of gallium-67 in AIDS.
(45/247)
We describe gastric localization of 67Ga in 13 patients with acquired immunodeficiency syndrome (AIDS) among 148 referred primarily to rule out Pneumocystis carinii pneumonia (PCP). Endoscopic biopsies in five of the patients indicated cytomegalovirus (CMV) infection in one, gastritis in two, and normal tissue in two. Other associated, but nongastric, infections in these 13 patients included esophageal candidiasis, PCP, Mycobacterium avium-intracellulare (MAI) complex, coccidioidomycosis, toxoplasmosis and Isospora belli. Only six of the patients exhibited gastric symptoms, and even fewer proved to have gastric pathology. Although gastric 67Ga uptake in a patient with AIDS may not require specific treatment, opportunistic infections as a possible cause of gastritis should be considered. (+info)
Colon carcinoma immunoscintigraphy by monoclonal anti-CEA antibody labeled with gallium-67-aminooxyacetyldeferroxamine.
(46/247)
Previous experimental results in nude mice showing that radiolabeling the monoclonal antibody anti-CEA 35 with 67Ga-aminooxyacetyldeferroxamine could give better tumor localization than radioiodination prompted us to initiate the present clinical study. The 67Ga-labeled antibody anti-CEA 35 (185 MBq, 0.7-1.7 mg) was injected preoperatively into 14 patients for colorectal carcinoma imaging. The same antibody labeled with 125I (3.7 MBq, 0.25 mg) was injected simultaneously to compare the 67Ga and 125I dose recoveries in surgical specimens. Twelve of 14 primary tumors gave a positive 67Ga scintigraph. The mean %ID/g recovered in all tumors 3-9 days after injection was significantly higher for 67Ga (0.019%) than for 125I (0.005%) (p < 0.001, paired t test). The tumor-to-normal tissue ratios were generally higher for 67Ga, with the exception of liver. We conclude that 67Ga-aminooxyacetyldeferroxamine improved immunoscintigraphy outside the liver, particularly in the pelvic region. We also show that deferroxamine infusion accelerates the excretion of 67Ga in eight patients and propose that this could lead to further improvement of immunoscintigraphy. (+info)
Gallium-67-citrate scanning in patients with sarcoid uveitis.
(47/247)
Gallium-67-citrate is useful for characterizing activity in patients with sarcoidosis. Gallium-67 uptake in bilateral symmetrical hilar lymphadenopathy and/or symmetrical salivary glands is typical of this clinical entity. Sarcoidosis is a systemic disease, and uveitis is considered the hallmark of ophthalmic sarcoidosis. We present two cases of ophthalmic sarcoidosis that shows uveal accumulation of 67Ga-citrate associated with clinical symptoms. (+info)
Simultaneous determination of gallium and indium with 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol in cationic micellar medium using derivative spectrophotometry.
(48/247)
A new derivative spectrophotometric method for rapid and selective trace analysis of Ga3+ and In3+ and for their simultaneous determination using 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol in a cationic micellar medium is reported. Molar absorptivity and Sandell's sensitivity of 1:1 Ga+ and In3+ complexes at their lambda(max) 553 nm and 558 nm are: 7.22 x 10(4) l mol(-1) cm(-1) and 5.85 x 10(4) l mol(-1) cm(-1), and 0.96 ng cm(-2) and 1.96 ng cm(-2), respectively. Linearity is observed in the concentration range 0.023-0.700 microg ml(-1) for gallium and 0.076-1.52 microg ml(-1) for indium; IUPAC detection limit is 0.012 and 0.035 ng ml(-1), respectively. These metal ions interfere with the determination of each other. However, 0.07-0.70 microg ml(-1) Ga3+ and 0.115-1.150 microg ml(-1) In3+ could be determined simultaneously when present together by the derivative method without any prior separation. The proposed procedures have been successfully applied for the individual and simultaneous determination of gallium and indium in synthetic binary mixtures, standard reference materials and environmental samples. (+info)