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  • 1
    Publication Date: 1993-10-01
    Description: Chronic granulomatous disease (CGD) is an inherited immunodeficiency resulting from the inability of an individual's phagocytes to produce superoxide anions because of defective NADPH oxidase. The disease may be treated by bone marrow transplantation and as such is a candidate for somatic gene therapy. Two thirds of patients have defects in an X- linked gene (X-CGD) encoding gp91-phox, the large subunit of the membrane cytochrome b-245 component of NADPH oxidase. Epstein-Barr virus-transformed B-cell lines from patients with CGD provide a model system for the disease. We have used retrovirus-mediated expression of gp91-phox to reconstitute functionally NADPH oxidase activity in B-cell lines from three unrelated patients with X-CGD. The protein is glycosylated and membrane associated, and the reconstituted oxidase is appropriately activated via protein kinase C. The kinetics of superoxide production by such reconstituted cells is similar to that of normal B-cell lines. These data show the potential of gene therapy for this disease.
    Print ISSN: 0006-4971
    Electronic ISSN: 1528-0020
    Topics: Biology , Medicine
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  • 2
    Publication Date: 1991-08-01
    Description: We reviewed magnetic resonance (MR) staging examinations of 98 patients with malignant lymphoma who failed other therapy and were under evaluation for bone marrow transplantation. MR scan results were compared with blind posterior iliac crest aspirations and biopsies. Images of vertebral, pelvic, and femoral marrow were obtained using a standard T1-weighted, short repetition time (TR), short time to echo (TE) (TR700/TE22), spin-echo (T1-SE) method in 92 patients and short TI inversion recovery (STIR) technique (TR1,500/TE36/TI100) in all. On standard T1-SE sequence, normal marrow is bright due to the predominance of marrow fat, and tumor is dark. With STIR images, water containing tumor has a very high signal intensity in a dark (fat suppressed) background. Thirteen patients had positive MR scans and marrow biopsies, whereas 49 had negative MR scans and biopsies. Of 36 discordant MR/histology results, 10 had positive biopsies and negative MR exams; eight of these had microscopic infiltration (less than or equal to 5%) with tumor. MR detected marrow tumor either in the crests or elsewhere in 25 of 75 (33%) patients with negative study biopsies. We could confirm marrow involvement in 15 of these 25 (60%) by clinical methods. Therefore, up to one third of the patients evaluated with routine biopsies may have occult marrow tumor detectable by MR exam. In patients with negative marrow biopsies, especially those with Hodgkin's disease or intermediate to high-grade non-Hodgkin's lymphomas, MR scans found focal lesions distant from the crests. Biopsy better detected lower grade microscopic involvement. We conclude that optimal marrow staging of lymphoma patients incorporates both biopsy and MR imaging.
    Print ISSN: 0006-4971
    Electronic ISSN: 1528-0020
    Topics: Biology , Medicine
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  • 3
    Publication Date: 1990-12-01
    Description: The relationship between the oral efficacy and the acute toxicity of hydroxypyridin-4-one iron chelators has been investigated to clarify structure-function relationships of these compounds in vivo and to identify compounds with the maximum therapeutic safety margin. By comparing 59Fe excretion following oral or intraperitoneal administration of increasing doses of each chelator to iron-overloaded mice, the most effective compounds have been identified. These have partition coefficients (Kpart) above 0.3 in the iron-free form with a trend of increasing oral efficacy with increasing Kpart values (r = .6). However, this is achieved at a cost of increasing acute toxicity, as shown by a linear correlation between 59Fe excretion increase per unit dose and 1/LD50 (r = .83). A sharp increase in the LD50 values is observed for compounds with Kpart values above 1.0, suggesting that such compounds are unlikely to possess a sufficient therapeutic safety margin. Below a Kpart of 1.0, acute toxicity is relatively independent of lipid solubility. All the compounds are less toxic by the oral route than by the intraperitoneal route, although iron excretion is not significantly different by these two routes. At least five compounds (CP51, CP94, CP93, CP96, and CP21) are more effective orally than the same dose of intraperitoneal desferrioxamine (DFO) (P less than or equal to .02) or orally administered L1(CP20) (P less than or equal to .02).
    Print ISSN: 0006-4971
    Electronic ISSN: 1528-0020
    Topics: Biology , Medicine
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  • 4
    Publication Date: 1994-10-15
    Description: Chronic granulomatous disease (CGD) results from defects in the phagocyte nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, central to which is the membrane-bound cytochrome b-245. The cytochrome is composed of two protein subunits, the larger (gp91-phox) being deficient in X-linked CGD. In this study, we have analyzed expression of the cytochrome subunits in B-cell lines from two autosomal CGD patients for whom the disease is caused by deficiency of p22-phox, the smaller subunit. We report the presence of a 65-kD precursor of gp91- phox in the membrane fraction of both p22-phox-deficient cell lines, corresponding to the core protein with N-linked carbohydrate side chains in the high mannose form. Expression of p22-phox in these cells resulted in functional correction of NADPH oxidase. In addition, gp91- phox in the reconstituted cells was processed to its terminally glycosylated form. These data suggest that the association of the 65-kD gp91-phox precursor with p22-phox is a prerequisite for processing of the carbohydrate side chains to the complex form in the Golgi. The detection of this precursor will enable characterization of mutations disrupting the subunit interaction (either naturally occurring or derived by in vitro mutagenesis) and so aid in structure-function analysis of cytochrome b-245. Reconstitution of p22-phox-deficient cells shows the potential of gene therapy for this autosomal form of CGD.
    Print ISSN: 0006-4971
    Electronic ISSN: 1528-0020
    Topics: Biology , Medicine
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  • 5
    Publication Date: 1991-11-15
    Description: Five orally effective iron chelators of the 3-hydroxypyridin-4-one series have been administered intraperitoneally to iron-overloaded and nonoverloaded male mice at a dose of 200 mg/kg/24 h for a total of 60 days to investigate the effect on iron loading and toxicity. There was a significant reduction in hepatic iron at the end of the study in the iron-overloaded mice with all compounds studied using chemical iron quantitation (P less than .001) and with Perls' stain (P less than .01). Liver iron removal with the hydroxypyridinones ranged from 37% with CP20 to 63% with CP51, compared with 46% removal for desferrioxamine (DFO). There was no significant reduction in splenic or cardiac iron with any chelator. There were no deaths in iron-overloaded animals receiving any of the hydroxypyridin-4-ones, but significantly more deaths in the nonoverloaded groups as a whole (P less than .03). No weight loss was observed with any chelator. Significant reductions in hemoglobin and white cell count were observed with CP20(L1). No histologic abnormalities of kidney, spleen, bone marrow, or stifle joints were observed. Intracytoplasmic inclusion bodies were observed in the centrilobular hepatocytes of animals administered each of the hydroxypyridin-4-ones, while the DFO-treated and control groups showed no such changes.
    Print ISSN: 0006-4971
    Electronic ISSN: 1528-0020
    Topics: Biology , Medicine
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  • 6
    Publication Date: 1994-10-15
    Description: Chronic granulomatous disease (CGD) results from defects in the phagocyte nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, central to which is the membrane-bound cytochrome b-245. The cytochrome is composed of two protein subunits, the larger (gp91-phox) being deficient in X-linked CGD. In this study, we have analyzed expression of the cytochrome subunits in B-cell lines from two autosomal CGD patients for whom the disease is caused by deficiency of p22-phox, the smaller subunit. We report the presence of a 65-kD precursor of gp91- phox in the membrane fraction of both p22-phox-deficient cell lines, corresponding to the core protein with N-linked carbohydrate side chains in the high mannose form. Expression of p22-phox in these cells resulted in functional correction of NADPH oxidase. In addition, gp91- phox in the reconstituted cells was processed to its terminally glycosylated form. These data suggest that the association of the 65-kD gp91-phox precursor with p22-phox is a prerequisite for processing of the carbohydrate side chains to the complex form in the Golgi. The detection of this precursor will enable characterization of mutations disrupting the subunit interaction (either naturally occurring or derived by in vitro mutagenesis) and so aid in structure-function analysis of cytochrome b-245. Reconstitution of p22-phox-deficient cells shows the potential of gene therapy for this autosomal form of CGD.
    Print ISSN: 0006-4971
    Electronic ISSN: 1528-0020
    Topics: Biology , Medicine
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  • 7
    Publication Date: 1991-08-01
    Description: We reviewed magnetic resonance (MR) staging examinations of 98 patients with malignant lymphoma who failed other therapy and were under evaluation for bone marrow transplantation. MR scan results were compared with blind posterior iliac crest aspirations and biopsies. Images of vertebral, pelvic, and femoral marrow were obtained using a standard T1-weighted, short repetition time (TR), short time to echo (TE) (TR700/TE22), spin-echo (T1-SE) method in 92 patients and short TI inversion recovery (STIR) technique (TR1,500/TE36/TI100) in all. On standard T1-SE sequence, normal marrow is bright due to the predominance of marrow fat, and tumor is dark. With STIR images, water containing tumor has a very high signal intensity in a dark (fat suppressed) background. Thirteen patients had positive MR scans and marrow biopsies, whereas 49 had negative MR scans and biopsies. Of 36 discordant MR/histology results, 10 had positive biopsies and negative MR exams; eight of these had microscopic infiltration (less than or equal to 5%) with tumor. MR detected marrow tumor either in the crests or elsewhere in 25 of 75 (33%) patients with negative study biopsies. We could confirm marrow involvement in 15 of these 25 (60%) by clinical methods. Therefore, up to one third of the patients evaluated with routine biopsies may have occult marrow tumor detectable by MR exam. In patients with negative marrow biopsies, especially those with Hodgkin's disease or intermediate to high-grade non-Hodgkin's lymphomas, MR scans found focal lesions distant from the crests. Biopsy better detected lower grade microscopic involvement. We conclude that optimal marrow staging of lymphoma patients incorporates both biopsy and MR imaging.
    Print ISSN: 0006-4971
    Electronic ISSN: 1528-0020
    Topics: Biology , Medicine
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  • 8
    Publication Date: 1991-11-15
    Description: Five orally effective iron chelators of the 3-hydroxypyridin-4-one series have been administered intraperitoneally to iron-overloaded and nonoverloaded male mice at a dose of 200 mg/kg/24 h for a total of 60 days to investigate the effect on iron loading and toxicity. There was a significant reduction in hepatic iron at the end of the study in the iron-overloaded mice with all compounds studied using chemical iron quantitation (P less than .001) and with Perls' stain (P less than .01). Liver iron removal with the hydroxypyridinones ranged from 37% with CP20 to 63% with CP51, compared with 46% removal for desferrioxamine (DFO). There was no significant reduction in splenic or cardiac iron with any chelator. There were no deaths in iron-overloaded animals receiving any of the hydroxypyridin-4-ones, but significantly more deaths in the nonoverloaded groups as a whole (P less than .03). No weight loss was observed with any chelator. Significant reductions in hemoglobin and white cell count were observed with CP20(L1). No histologic abnormalities of kidney, spleen, bone marrow, or stifle joints were observed. Intracytoplasmic inclusion bodies were observed in the centrilobular hepatocytes of animals administered each of the hydroxypyridin-4-ones, while the DFO-treated and control groups showed no such changes.
    Print ISSN: 0006-4971
    Electronic ISSN: 1528-0020
    Topics: Biology , Medicine
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  • 9
    Publication Date: 1993-10-01
    Description: Chronic granulomatous disease (CGD) is an inherited immunodeficiency resulting from the inability of an individual's phagocytes to produce superoxide anions because of defective NADPH oxidase. The disease may be treated by bone marrow transplantation and as such is a candidate for somatic gene therapy. Two thirds of patients have defects in an X- linked gene (X-CGD) encoding gp91-phox, the large subunit of the membrane cytochrome b-245 component of NADPH oxidase. Epstein-Barr virus-transformed B-cell lines from patients with CGD provide a model system for the disease. We have used retrovirus-mediated expression of gp91-phox to reconstitute functionally NADPH oxidase activity in B-cell lines from three unrelated patients with X-CGD. The protein is glycosylated and membrane associated, and the reconstituted oxidase is appropriately activated via protein kinase C. The kinetics of superoxide production by such reconstituted cells is similar to that of normal B-cell lines. These data show the potential of gene therapy for this disease.
    Print ISSN: 0006-4971
    Electronic ISSN: 1528-0020
    Topics: Biology , Medicine
    Location Call Number Expected Availability
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  • 10
    Publication Date: 1990-12-01
    Description: The relationship between the oral efficacy and the acute toxicity of hydroxypyridin-4-one iron chelators has been investigated to clarify structure-function relationships of these compounds in vivo and to identify compounds with the maximum therapeutic safety margin. By comparing 59Fe excretion following oral or intraperitoneal administration of increasing doses of each chelator to iron-overloaded mice, the most effective compounds have been identified. These have partition coefficients (Kpart) above 0.3 in the iron-free form with a trend of increasing oral efficacy with increasing Kpart values (r = .6). However, this is achieved at a cost of increasing acute toxicity, as shown by a linear correlation between 59Fe excretion increase per unit dose and 1/LD50 (r = .83). A sharp increase in the LD50 values is observed for compounds with Kpart values above 1.0, suggesting that such compounds are unlikely to possess a sufficient therapeutic safety margin. Below a Kpart of 1.0, acute toxicity is relatively independent of lipid solubility. All the compounds are less toxic by the oral route than by the intraperitoneal route, although iron excretion is not significantly different by these two routes. At least five compounds (CP51, CP94, CP93, CP96, and CP21) are more effective orally than the same dose of intraperitoneal desferrioxamine (DFO) (P less than or equal to .02) or orally administered L1(CP20) (P less than or equal to .02).
    Print ISSN: 0006-4971
    Electronic ISSN: 1528-0020
    Topics: Biology , Medicine
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