Bone mass and microarchitecture of irradiated and bone marrow-transplanted mice: influences of the donor strain

Total body irradiation and bone marrow transplantation induced dramatic trabecular bone loss and cortical thickening in mice. Transplanted cells were engrafted in bone marrow, along trabeculae, and in periosteal and endosteal envelopes. None of the osteocytes were of donor origin. Bone microarchitecture of transplanted mice changed to tend toward the donor phenotype.

INTRODUCTION

Osteopenia and osteoporosis are complications of bone marrow transplants (BMT) attributed to related chemotherapy. However, the specific influence of total body irradiation (TBI) is unknown.

METHODS

We investigated the effects of TBI and BMT on bone mass and microarchitecture by micro-CT. Eighteen C57Bl/6 (B6) mice receiving lethal TBI had a BMT with marrow cells from green fluorescent protein--transgenic-C57Bl/6 (GFP) mice. Transplanted (T(GFP)B6), B6, and GFP mice were euthanized 1, 3, and 6 months after BMT or at a related age.

RESULTS

T(GFP)B6 presented a dramatic bone loss compared with B6 and did not restore their trabecular bone mass over time, despite a cortical thickening 6 months after BMT. Serum testosterone levels were not significantly reduced after BMT. During aging, GFP mice have less trabeculae, thicker cortices, but a narrower femoral shaft than B6 mice. From 3 months after BMT, cortical characteristics of T(GFP)B6 mice differed statistically from B6 mice and were identical to those of GFP mice. GFP(+) cells were located along trabecular surfaces and in periosteal and endosteal envelopes, but none of the osteocytes expressed GFP.

CONCLUSION

Our findings suggest that engrafted cells did not restore the irradiation-induced trabecular bone loss, but reconstituted a marrow microenvironment and bone remodeling similar to those of the donor. The effects of irradiation and graft on bone remodeling differed between cortical and trabecular bone.

Isolation of osteoprogenitors from murine bone marrow by selection of CD11b negative cells

Selection of cells having the most osteogenic potential is a strategy used in bone tissue engineering. Preclinical studies using murine bone marrow cells must consider the large amount of hematopoietic cells in the adherent fraction. The aim of this study was to enrich a murine bone marrow cell population with osteoprogenitors by using a simple and reliable method. Bone marrow from C57Bl/6 mice was extracted and cells which adhered onto plastic were expanded in primary culture for 14 days. Immunolabeling of the CD11b surface antigen was performed and the CD11b(-) cell fraction was isolated by FACS. Sorted and unsorted populations were analyzed for gene expression of osteoblast differentiation, alkaline phosphatase (AlkP) activity and matrix mineralization capacities. Selection of CD11b(-) cells increased the number of AlkP(+) cells from the plastic adherent fraction from 6.3% +/- 0.8 to 56% +/- 3.3 with a sevenfold increase in AlkP activity. mRNA analysis revealed a significant increase in the CD11b(-) fraction for Osterix (41-fold), RANKL (17-fold), M-CSF (8-fold) and Runx-2 (8-fold). An osteogenic population was obtained with improved capacities to produce a mineralized extracellular matrix in vitro, independently of the presence of glucocorticoids in the culture medium.

Disuse and orchidectomy have additional effects on bone loss in the aged male rat

INTRODUCTION

A severely osteopenic rat model was obtained by combining orchidectomy (ORX) and disuse (due to local paralysis induced by botulinum toxin [BTX] in the quadriceps muscle).

METHODS

Forty-two aged male rats (5-6 months old) were randomized into three groups: 18 were SHAM operated; 6 were ORX; and 18 were ORX and BTX injected in the right hindlimb. One, two, and three months after surgery, bone mass (BV/TV) and microarchitectural parameters (Tb.Th, Tb.N, Tb.Sp, Tb.Pf, and structure model index [SMI]) were measured by microcomputed tomography (microCT) on the primary and secondary spongiosa of the femur. Osteoid parameters (OS/BS, O.Th), the number of osteoclasts (Nb.Oc), and the mineral apposition rate (Ct.MAR, Cn.MAR) were measured by histology. The serum tartrate-resistant acid phosphatase (TRAcP) 5b activity was measured by immunoassay.

RESULTS

ORX induced a decrease of BV/TV, Tb.N and an increase of Tb.Sp, Tb.Pf, and SMI on both primary and secondary spongiosa. ORX and BTX had cumulative effects on bone loss, since differences were maximized on the right femur. The decrease in BV/TV reached -65%. Osteoid parameters and mineral apposition rate increased during the time course of the study. A peak of serum TRAcP was found at 7 days post-ORX. TRAcP levels reached the highest values in the ORX-BTX groups and the effect lasted longer than in the group with ORX alone. The association of ORX-BTX induced a greater bone resorption, due to the removal of complete trabeculae, compared to ORX alone.

CONCLUSION

This model induced a severe and rapid bone loss and can be used to explore pharmacological- and biomaterial-based countermeasures.

Evaluation of an injectable bone substitute (betaTCP/hydroxyapatite/hydroxy-propyl-methyl-cellulose) in severely osteopenic and aged rats

The use of injectable biomaterials is of interest in osteoporotic patients to locally restore bone mass in sites at risk of fracture. An injectable bone substitute (IBS1 made of betaTCP/hydroxyapatite as a calcium phosphate substitute and hydroxy-propyl-methyl-cellulose as a polymer carrier) was used in a severely osteopenic rat model obtained by combining orchidectomy (ORX) and disuse (paralysis induced by botulinum toxin - BTX). Fifty-six aged male rats were randomized into three groups: 18 were SHAM operated; 38 were ORX and BTX injected in the right hindlimb; they constituted the OP (osteoporotic) group. One month after ORX-BTX surgery, 20 of these OP rats received a IBS1 injection in the right femur (OP-IBS1 rats). Animals were studied at the time of IBS1 injection 1 month post ORX-BTX (M1), 1 month (M2) and 2 months (M3) after IBS1 injection. Bone mass (BV/TV) and microarchitectural parameters were measured by microCT. BV/TV was decreased after ORX-BTX; ORX and BTX had cumulative effects on bone loss (differences maximized on the right femur). BV/TV (combining the volume of both bone and material in OP-IBS1 rats) was elevated at M1 but decreased at M2. Marked bone formation was found onto the biomaterial granules but bone had a woven texture. A marked increase in the number of nonosteoclastic TRAcP+ cells was found in the implanted area. IBS1 induced new bone formation shortly after implantation but both IBS1 and woven bone were resorbed without inducing lamellar bone. Biomaterial trials must be conducted with long-term implantation periods, in aged osteoporotic animals.

Comparative effects of five bisphosphonates on apoptosis of macrophage cells in vitro

Bisphosphonates (BPs) inhibits bone resorption by reducing osteoclastic activity; they induce osteoclast apoptosis. Pathophysiology of prostheses loosening is complex and implies an inflammatory reaction secondary to the phagocytosis of wear debris by macrophages with a secondary increased bone resorption by osteoclasts. BPs inhibit proliferation and cause cell death in macrophages by induction of apoptosis. We have used mouse macrophage-like J774.1 cells to evaluate the effects of five BPs. J774A.1 cells were cultured in a standard culture medium for 2-days. BPs (alendronate, pamidronate, etidronate, risedronate, zoledronic acid) were added in the medium at concentration of 10(-6) to 10(-4)M during 3 days. Cells were studied by fluorescence microscopy after staining with the fluorescent dye Hoescht H33342 and the percentage of apoptotic cells was determined on 300 nuclei. Cells were analyzed by flow cytofluorometry after staining with annexin V-FITC (for counting apoptotic cells) and propidium iodide (for necrotic/late-apoptotic cells) on 2000 cells. Etidronate did not cause significant apoptosis or necrosis, at any concentration. Alendronate and pamidronate caused apoptosis and death only at very high concentration [10(-4)M]. On the contrary, apoptotic and necrotic cells were evidenced with risedronate or zoledronic acid at lower concentrations. These effects were dose-dependant and occurred when concentration reached [10(-5)M]. The number of apoptotic cells was higher with zoledronic acid and then with risedronate. Cytofluorometry appeared superior to cytologic analysis in the investigation of macrophage apoptosis, since necrotic cells loose contact with the glass slides and are not identifiable in cytological counts. Some amino-BPs appear to induce apoptosis in macrophages.

Relations between Radiograph Texture Analysis and Microcomputed Tomography in Two Rat Models of Bone Metastases

AIMS

Osteolytic (Walker 256, W256) and osteoblastic (MatLyLu, MLL) metastases were induced to investigate their effect on bone architecture by microcomputed tomography (microCT) and texture analysis of radiographs.

METHODS

Fischer and Copenhagen rats received an intracardiac injection with W256/MLL cells, respectively. Femur and tibia radiographs were analyzed by texture analysis with run lengths and fractal algorithms. Microarchitecture was analyzed on primary and secondary spongiosa by microCT.

RESULTS

W256 and MLL induced a decrease of trabecular bone mass, a disconnection of trabeculae and an increased conversion of plates into pillars. On radiographs and 3-dimensional models of W256 rats, a disappearance of the primary spongiosa was observed. On radiographs and 3-dimensional models of MLL rats, osteolytic lesions were observed as disseminated dark areas. Run length and fractal analyses were altered in both metastases.

CONCLUSION

W256 and MLL cells induced two different patterns of osteolysis. Texture analysis of radiographs is a useful technique to explore trabecular bone changes.

Biodegradability of poly (2-hydroxyethyl methacrylate) in the presence of the J774.2 macrophage cell line

The degradation of cross-linked and linear poly(2-hydroxyethyl methacrylate) (pHEMA), was examined in vitro with J774.2 cells. pHEMA microbeads were prepared with both types of polymers. Only cells in contact with the microbeads increased their production of lysosomal enzymes (TRAcP and ANAE) and released large amounts of reactive oxygen species with both types of pHEMA microbeads. Electron microscopy showed that macrophages were able to erode the surface of linear pHEMA but unable to erode the surface of the cross-linked polymer. Cells appeared wrapped by the linear pHEMA surface, but those cultured on the cross-linked polymer were only laying at the surface. After cell culture, the surface roughness of pHEMA slices was observed by atomic force microscopy (AFM). There was a significant increase in roughness (R(a)) of the surface of linear pHEMA slices cultured with J774.2 cells whereas no difference in R(a) between the surface of cross-linked pHEMA slices could be measured. AFM image of the hydrated materials were done: the surface of linear pHEMA swelled considerably in saline whereas the hydrated cross-linked polymer did not differ from the air-dried appearance. In conclusion, linear pHEMA swells in biological fluids, activates macrophages in close contact with the polymer and can be progressively eroded.

Comparison of histomorphometric descriptors of bone architecture with dual-energy X-ray absorptiometry for assessing bone loss in the orchidectomized rat

We have compared different methods for measuring bone loss in the orchidectomized (ORX) rat model of male osteoporosis: densitometry (DXA), ash weight, anatomic bone indices, histomorphometry and two-dimensional trabecular architecture analysis. Forty-eight male Wistar rats were studied at 2, 4, 8 and 16 weeks (four groups). In each group, 6 rats were ORX and 6 sham-operated were used as control. DXA was performed on the whole body, tibia and femur. Histomorphometry was performed on the secondary spongiosa of the tibia: trabecular bone volume (BV/TV) and trabecular characteristics (number, separation and thickness) were measured. Architecture analysis comprised strut identification, star volume of the marrow spaces and trabeculae, Euler-Poincaré number (E) and Kolmogorov fractal dimension (Dk). Bone mineral densities of the whole body, tibia and femur were reduced at 16 weeks in the ORX group. BV/TV was significantly decreased in the ORX group from the fourth week. Differences in the sensitivity of the architectural methods were found. There were no differences in trabecular thickness nor in trabecular star volume between ORX and controls even after 16 weeks. E became different at 8 weeks. Trabecular number, node count, star volume of the marrow spaces and trabecular separation became significantly different at 4 weeks Dk was modified after 2 weeks (p < 0.05 at 2 weeks, p < 0.001 from 4 weeks). In the ORX model, Dk appeared the most potent descriptor of trabecular bone disorganization by revealing the earliest changes at the network level.

Synthesis, characterization and comparative biodistribution study of a new series of p-iodine-125 benzamides as potential melanoma imaging agents

Iodobenzamides are reported to possess some affinity for melanoma. In order to identify the compound having the most appropriate pharmacokinetic properties as a potential melanoma imaging agent, thirteen new [125I]radioiodobenzamides with a butylene amide-amine spacer and various substituents on the terminal amino group were investigated. Their synthesis, radioiodination and biodistribution in B16 melanoma bearing C57BL6 mice are described and compared to [125I] labeled N-(2-diethylaminoethyl)-4-iodobenzamide ([125I]BZA), our reference compound. Changes in the terminal amino constituents induced modifications of lipophilicity, tumor uptake and organ distribution. The dimethylaminobutyl iodobenzamide appeared to be the most promising radiopharmaceutical imaging agent for the detection of melanoma and its metastases.

Distribution of I-BZA (N-2-diethylaminoethyl-4-iodobenzamide) in grafted melanoma and normal skin: a study by secondary ion mass spectroscopy

Iodobenzamides labelled with radioactive iodine are undergoing clinical evaluation as imaging and potential therapeutic agents in malignant melanomas. However, the uptake mechanism in melanic tissues remains controversial. Using secondary ion mass spectrometry (SIMS), we studied the microscopic distribution of N-(2 diethylaminoethyl)-4 iodobenzamide (I-BZA) in B16 murine melanoma inoculated to C57BL/6J1 Co mice as well as in normal pigmented skin. SIMS provides specific detection of iodine-127 atoms entering 127I-BZA composition. In B16 melanoma, 127I-BZA distribution was found to be heterogeneous, with focal areas of high concentration corresponding to cells rich in melanin pigments. In skin, SIMS analysis showed 127I-BZA distribution appearing as multiple small selective concentration areas within the epidermis. The number of these foci decreased from the stratum basale towards the stratum corneum. In both tissues, the intracellular location appeared specifically intracytoplasmic, with no apparent nuclear uptake. Distribution of this molecule mirrored that of melanin pigments. There was no enhancement of uptake at the membrane site. These results suggest that, in melanic tumors as well as in normal pigmented tissue, specific uptake of 127I-BZA occurs in pigment cells, with a possible link to melanin pigments.

Lean, fat and bone masses are influenced by orchidectomy in the rat. A densitometric X-ray absorptiometric study

In man, hypogonadism is a risk factor for osteoporosis. Orchidectomy (ORX) in the rat leads to an imbalance between resorption and formation resulting in bone loss. We have measured whole body weight, lean and fat mass, whole bone mass (BMC) in the ORX rat model by dual X-ray densitometry (DXA). Forty-eight male Wistar rats (18-19 weeks old) were studied at 2, 4, 8 and 16 weeks. In each group, 6 rats were ORX and 6 sham-operated were used as control. DXA was performed on the whole body and isolated tibia. The whole body weight of the ORX animals became significantly decreased only at 16 weeks. Whole body BMC was reduced from 8 weeks in the ORX group. The most striking result was a net decrease in lean mass that reached -15.7% at 16 weeks. On the other hand, fat mass remained unchanged during the time series in the ORX animals.

Comparison insight dual X-ray absorptiometry (DXA), histomorphometry, ash weight, and morphometric indices for bone evaluation in an animal model (the orchidectomized rat) of male osteoporosis

We have compared the measurements obtained by different methods: dual energy X-ray absorptiometry (DXA), histomorphometry, ash weight, and two morphometric indices (robusticity and bone weight/bone length index) in the orchidectomized (ORX) rat model of male osteoporosis. We examined 144 male wistar rats: 48 sham-operated, 48 ORX, and 48 ORX-treated with a bisphosphonate (risedronate) 2 or 10 mg/kg/day, 5 days per week. Rats were sacrificed at 2, 4, 8, or 16 weeks after the beginning of the study. DXA was performed on a Hologic QDR 2000 on the whole body, whole tibia, and tibial metaphysis. Bone volumes (C.BV/C.TV, and BV/TV) were measured by histomorphometry on the proximal tibial. A significant correlation was obtained between weight measured by DXA and scale (r = 0.993, P <0.000001). However, DXA underestimated weight by 0.3%. This discrepancy was dependent on the rat's weight. The weight bone length (WL) index was linearly correlated with BMD (r = 0.86), BMC (r = 0.96), and ash weight (r = 0.97). Correlation with robusticity was lower than with the WL index. A significant correlation was found between BMC of the metaphyseal region and the bone volumes but this explained only 27% of the variance; correlation with BMD was poorer (r = 0.40). BMC and ash weight were highly correlated (r = 0.992, P <0.000001). However, DXA overestimated BMC by 11% and the overestimation was found to be clearly dependent on the net mineral content of the bone.

Constitutive PI3-K activity is essential for proliferation, but not survival, of Theileria parva-transformed B cells

Theileria is an intracellular parasite that causes lymphoproliferative disorders in cattle, and infection of leucocytes induces a transformed phenotype similar to tumour cells, but the mechanisms by which the parasite induces this phenotype are not understood. Here, we show that infected B lymphocytes display constitutive phosphoinositide 3-kinase (PI3-K) activity, which appears to be necessary for proliferation, but not survival. Importantly, we demonstrate that one mechanism by which PI3-K mediates the proliferation of infected B lymphocytes is through the induction of a granulocyte-monocyte colony-stimulating factor (GM-CSF)-dependent autocrine loop. PI3-K induction of GM-CSF appears to be at the transcriptional level and, consistently, we demonstrate that PI3-K is also involved in the constitutive induction of AP-1 and NF-kappaB, which characterizes Theileria-infected leucocytes. Taken together, our results highlight a novel strategy exploited by the intracellular parasite Theileria to induce continued proliferation of its host leucocyte.

Gamma irradiation of human bone allografts alters medullary lipids and releases toxic compounds for osteoblast-like cells

The uncertainties about the transmission of prion proteins from xenogenic grafts prepared from bovine bone has led to the reconsideration of allogenic bone as a grafting material. Allografting is a complementary technique to autografting nowadays when large bone volumes are necessary. Several preparation techniques have been proposed. Fresh-frozen, freeze-dried and gamma irradiation are the most common. However, a large amount of lipids is present in the medullary spaces (near 70% in weight for a human femoral head). They are known to strongly influence the biocompatibility of the bone graft. The exact changes of lipids upon the sterilization and storage processes are poorly known. The aims of the present study were to appreciate the effects of gamma irradiation on medullary lipids and to identify the cytotoxicity of gamma-irradiated bank bone with/without lipid on cultures of osteoblast-like cells. Bone cores from 8 femoral heads retrieved during prosthesis surgery for arthritis were prepared with a drilling trephine. Cores were either sterilized by gamma radiations (25000 gray) or kept frozen until lipid extraction and lipofuschine-like dosage by Folch's method and fluorometric study. Peroxidated lipids appeared 2 to 3-fold higher in the gamma-irradiated cores than in frozen ones. Slices were prepared from bone cores and were transferred on confluent osteoblast-like cell layers (Saos-2). The raw slices (containing lipids) did not induce cell death. On the other hand, cell death was dramatically increased around the gamma-irradiated slices. Defatted slices which had been sterilized by gamma radiations or UV did not induce cell death. Defatting procedures should be added when preparing bone allografts in human bone banks.

Theileria annulata in CD5(+) macrophages and B1 B cells

Theileria parasites infect and transform bovine leukocytes. We have analyzed laboratory-established Theileria sp.-infected leukocyte lines and observed that transformed macrophages express CD5. Low-level expression of CD5 by macrophages was further confirmed on three independent Theileria annulata clinical isolates from Tunisia. Interestingly, the fourth CD5(+) clinical isolate (MB2) was morphologically different, expressed surface immunoglobulin M (IgM) and BoLA class II, and had rearranged Ig light-chain genes. To demonstrate that MB2 did indeed contain CD5(+) B cells, individual clonal lines were obtained by limiting dilution, and CD5 expression and Ig gene rearrangement were confirmed. This suggests that in natural infections T. annulata can invade and transform CD5(+) B cells.

Evaluation in mice of some iodinated melanoma imaging agents using cryosectioning and multi-wire proportional counting

AMBIS 4000, a multi-wire proportional counter, was calibrated for iodine-125 measurements. The detector displayed a linear response over a wide dynamic range. Using whole-body mice cryosections, a linear relationship could be established between count rate per area (cpm/mm2) measured with the AMBIS 4000 detector and the count rate per gram (dpm/g) determined with an NaI(Tl) scintillation detector. A calibration curve could, thus be constructed. This new method allowed direct visual and quantitative evaluation of the biodistribution of a short series of 125I-labelled benzamides in melanoma-bearing mice. All the compounds studied showed good tumoral targeting ability. For one of them, ortho-N-(2-diethylaminoethyl)-4-iodobenzamide, liver and lung uptake decreased rapidly after dosing, making it a suitable tracer for scintigraphic detection of malignant melanoma.

Upregulation of Jun and Fos family members and permanent JNK activity lead to constitutive AP-1 activation in Theileria-transformed leukocytes

Theileria parasitises bovine leukocytes and transforms them into proliferating, metastatic tumours, where the infection resembles a leukaemia-like disease. We have studied the signal transduction pathways leading to activation of the transcription factor AP-1 in different transformed leukocytes. Parasite infection leads to an up-regulation of all members of the Jun/Fos family of proteins and surprisingly, this occurs in the absence of any detectable ERK, or p38 MAP kinase activity. In the parasitised B-sarcoma TBL3, AP-1 induction occurs in the absence of any JNK activity. In contrast, in infected macrophage and B-cell lines, AP-1 transcriptional activity is strictly associated with the parasite-induced constitutive activation of JNK and subsequent c-Jun N-terminal phosphorylation. Thus, constant AP-1 transcriptional activity involves both an upregulation in the levels of Jun and Fos proteins and constitutive JNK activation.

Free radicals and side products released during methylmethacrylate polymerization are cytotoxic for osteoblastic cells

Polymerization of orthopedic cements makes use of a peroxide initiator which is decomposed by an accelerator to provide free radicals. Free radicals which act on the monomer molecules are also known to induce cell lesions and cell death. We used an in vitro model of cement polymerization to study the effects of free radicals release on osteoblast-like cells. Initiation of methylmethacrylate was done with benzoyl peroxide and acceleration by N,N-dimethylaniline. Bulk polymerization was done in calibrated test tubes which were left aging until use. Polymers (aged from J1 to J31 days after completion of the polymerization process) were sawed to produce slices. Slices were rinsed in distilled water and free radical release was measured by spectrophotometric titration with p-iodonitrotetrazolium. Saos-2 osteoblast-like cells were cultured in parallel on the slices. Cells appeared to be round and were altered when grown on slices prepared freshly after polymerization. Cytomorphometric analysis of the cell shape (surface area and form-factor polyethylene confirmed that they spread and flatten on slices prepared a long time after polymerization. Free radical release from polymethylmethacrylate cements is a long-lasting event that can induce bone cells alterations in their neighborhood. Two cytotoxic mechanisms were evidenced: (a) polymer slices released a stable toxic component which could be removed by extensive washing; (b) they released free radicals which were still detectable several days after the end of polymerization. The titration curve was a negative exponential.

A new quantitative method to evaluate the biodistribution of a radiolabelled tracer for melanoma using whole-body cryosectioning and a gaseous detector: comparison with conventional tissue combustion technology

Whole-body autoradiography (WBA) and multi-wire proportional counting allow for spatial imaging of the radioactive material present in the tissues and organs of dehydrated animal sections. AMBIS 4000 counting of whole-body cryosections offers a sensitive, accurate and reproducible novel method for the quantitative measurement of the tissue distribution of a [14C] radiopharmaceutical. Intensity of AMBIS 4000 counting (net cpm/mm2) and concentration of radioactivity (nCi/g) were linearly related, yielding a standard curve. Evaluating biodistribution (a) provides pharmacokinetic data for predicting the potential tissue deposition of an absorbed dose of radioactivity in man, and (b) allows visual and quantitative evaluation of radioactivity in small anatomical structures that otherwise could not be detected by conventional tissue combustion technology. This new method of WBA, coupled with AMBIS 4000 counting, should prove a valuable method for pharmacodynamic studies, and afford a predictive tool for nuclear medicine by assessing specific targeting of selected tissues.

Clinical study of [123I] N-(2-diethylaminoethyl)-4-iodobenzamide in the diagnosis of primary and metastatic ocular melanoma

PURPOSE

To assess the value of scintigraphy with [123I]N-(2-diethylaminoethyl)-4-iodobenzamide (BZA), a phase II clinical trial was performed on 48 patients with a suspicion of ocular melanoma.

METHODS

56 examinations were performed to image lesions with a clinical diagnosis of primary ocular melanoma before and/or after treatment, to observe the results in simulating lesions or to image metastases.

RESULTS

Ocular BZA-scintigraphy demonstrated a sensitivity of 86%, and a specificity of 83%. Whole-body scintigraphy was used in the follow-up of treated patients and could be repeated. We imaged orbital recurrence, known and occult metastases, specially in the liver. After 9 conservative treatments ocular BZA-scintigraphy was negative in 9 eyes.

CONCLUSION

The BZA-scintigraphy in combination with other diagnostic procedures appeared to be a suitable method in the diagnosis of ocular melanoma and a potentially useful imaging modality to screen for ocular malignant melanoma metastases.

Application of textural features to the detection of ocular melanomas in scintigraphy

A method for automated detection of ocular melanoma in scintigraphic images is described. The algorithm first performs an automatic segmentation of the eyes on specific reference images. The images of the eyes are then analyzed using textural parameters computed in several directions and averaged to damp directional information. Assuming that only one eye per patient will be pathological, the ratio of the textural parameters of the two eyes is computed. A statistical analysis is performed over these ratios to select the most highly discriminating textural parameters and detect the pathological patients. The method has been tested successfully on a population of 23 individuals and we found significant differences between pathological and normal patients.

Fusion of Leishmania amazonensis parasitophorous vacuoles with phagosomes containing zymosan particles: cinemicrographic and ultrastructural observations

Studies on fixed preparations have shown that vacuoles containing zymosan (Z) particles internalized by infected macrophages can selectively fuse with the large parasitophorous vacuoles (PVs) that shelter Leishmania amazonensis. To examine the kinetics of vacuolar fusion in individual cells, particles were followed by time-lapse cinemicrography from their uptake to their entry in a PV. Newly formed Z-containing vacuoles moved centripetally and, if they contacted a PV, the two vacuoles remained closely apposed for variable, often extended, periods of time before they eventually fused. Transmission electron microscopy confirmed that the cytoplasm separating the partner vacuoles could be reduced to a very thin layer. Initiation of fusion was indicated by reduced refractility of the boundary between Z vacuoles and target PVs. Within a few minutes the PV enlarged and encompassed the Z particles, which remained immobile throughout. The interval between phagocytosis and fusion, 50 +/- 7.4 min (N = 17; range, 4 to 108 min), suggests that most but not all Z vacuoles underwent significant maturation by the time of fusion. Some particles were transferred singly, others entered PVs in groups of 2 or more, and additional clustered transfers to the same vacuole were also observed. These observations provide a baseline for studies of the biochemical mechanisms and the pharmacological control of the fusion of Leishmania PVs, and for the comparison of the fusion behavior of the PVs with that of other phagocytically derived vacuoles.

Localization of N-(2-diethylaminoethyl)4-iodobenzamide in the pigmented mouse eye: a microanalytical study

The 123I-N-(2-diethylaminoethyl)4-iodobenzamide (123I-BZA) is a new radiopharmaceutical used for the scintigraphic imaging of malignant melanomas. The mechanism for BZA uptake in melanic tissues is still unknown. Two methods of microanalysis, secondary ion mass spectrometry and electron probe X-ray microanalysis, were used to determine tissue distribution and subcellular location of unlabelled BZA in the C57BL6/J1 co mouse eye. Microanalysis showed elective BZA uptake by the pigmented structures of the eye: choroidal melanocytes and retinal pigment cells, where it was specifically located within melanosomes. The tropism of BZA for melanic tumours, as well as for normal pigmented tissues, could be explained by a high affinity for the melanin pigment.

Synthesis, radiolabeling, and preliminary evaluation in mice of some (N-diethylaminoethyl)-4-iodobenzamide derivatives as melanoma imaging agents

N-(2-Diethylaminoethyl)-4-iodobenzamide (BZA) is a radiopharmaceutical recently developed in our laboratory for the scintigraphic detection of melanoma and metastases. Optimal time for imaging was between 18-24 h p.i. of [123I] BZA. With a view to selecting compounds able to provide quality images shortly after the injection, synthesis of an initial series of BZA derivatives and their evaluation in B16 melanoma bearing mice have been carried out. The [125I] radiolabeled products were obtained by a simple isotopic exchange procedure with high radiochemical yields (85-95%). After i.v. administration of the compounds we observed a good tumoral targeting ability. Tumoral activity peaked at 2.6 to 7.70% injected dose per g within 1 h post-injection. One of the benzamides with a blood clearance faster than that of BZA--0.06 vs. 0.2% I D/g--6 h p.i. gave the same tumor to blood and to organ ratios as BZA at 12-18 h p.i. Based on these preclinical data we hope to obtain good tumoral images 6 h p.i. in scintigraphic studies in man.

Fusion between large phagocytic vesicles: targeting of yeast and other particulates to phagolysosomes that shelter the bacterium Coxiella burnetii or the protozoan Leishmania amazonensis in Chinese hamster ovary cells

This report examines the fusion of phagocytic vesicles with the large phagolysosome-like vacuoles induced in Chinese hamster ovary cells by the bacterium Coxiella burnetti or the Protozoan flagellate Leishmania amazonensis. Infection by these organisms is compatible with cell survival and multiplication. Fusion was inferred from the transfer of microscopically identifiable particles from donor to target vesicles. Donor vesicles contained heat-killed yeast, zymosan, beta-glucan or latex beads taken up by the host cells. Yeast and zymosan were also coated with Concanavalin A to increase their uptake by the cells (Goldman, R., Exp. Cell Res. 104, 325–334, 1977). Particle localization, routinely ascertained by phase-contrast microscopy, was confirmed by confocal laser fluorescence and by transmission electron microscopy. Coxiella vacuoles admitted all the particles tested and transfer took place whether the particles were given to the cells prior to or after infection. Transfer of uncoated or Concanavalin-A-coated yeast or zymosan was dependent on the number of particles ingested and on the incubation period (between 2 and 24 hours). Furthermore, the transfer step was quite efficient, since over 85% of the particles ingested entered Coxiella vacuoles at all particle to cell ratios examined. The fraction of uncoated or Concanavalin-A-coated yeast or zymosan transferred to Leishmania vacuoles was consistently lower and diminished at higher particle loads. In addition, only rarely did latex beads enter these vacuoles. The models proposed may be useful for the delineation of biochemical and molecular mechanisms involved in the fusion of large phagocytic vesicles and the modulation of the latter by cellular and pathogen-derived signals.

Phase II scintigraphic clinical trial of malignant melanoma and metastases with iodine-123-N-(2-diethylaminoethyl 4-iodobenzamide)

Preclinical studies established [125I]-N-(2-diethylaminoethyl) 4-iodobenzamide (BZA) as a potential radiopharmaceutical in the management of patients with malignant melanoma. External detection of both murine and human melanotic melanomas was possible after intravenous injection of 125I-BZA in tumor-bearing mice. This article reports a Phase II clinical trial evaluating 123I-BZA as an imaging agent of primary melanomas and metastases. A total of 110 patients with a history of melanoma were investigated in two nuclear medicine departments. Subjects were imaged from 20 to 24 hr after the intravenous injection of 3.5 mCi (130 MBq) of 123I-BZA. After injection, no short-term or long-term side effects were noted. Calculated on a lesion-site basis, diagnostic sensitivity was 81%, accuracy was 87% and specificity was 100%. The melanoma nature of previously occult lesions was confirmed by clinical criteria and/or additional investigations in follow-up studies. The scintigraphies were normal in 44 patients in clinical remission after treatment of malignant melanoma and in seven patients with nonmelanoma disease. No false positive results were observed. Iodine-123-BZA scintigraphy appears to be a safe and useful agent for the detection and follow-up of patients with malignant melanoma. BZA also allowed the detection of unsuspected lesions and the evaluation of the results of various therapeutic procedures such as surgery, chemotherapy, immunobiology, biological therapy or radiotherapy.

Biodistribution and metabolism of orally administered mitozolomide in mice

The disposition and metabolism of two 14C-labeled species of Mitozolomide (Mz) were studied in healthy and in B16 melanoma-bearing mice after po administration of a 40 mg/kg dose. Urine was the main elimination route of the radioactivity derived from [14C]chloroethyl Mz whereas a major part of the radiocarbon was recovered as 14CO2 in the expired air of mice given C]tetrazin Mz, indicating an extensive metabolism of the drug. Subsequent studies conducted only with the [14C]chloroethyl species, showed that total radioactivity and Mz were rapidly distributed to plasma and tissues but that Mz levels decreased more rapidly than those of total radioactivity, thus indicating an early metabolism of the drug. It is noteworthy that B16 melanoma concentrated Mz and/or metabolites to the same extent as normal tissues except the brain. Elimination of Mz from all tissues including the tumor was first order with a t 1/2 ranging from 1.52 to 2.03 hr. In the part of the study related to disposition, pharmacokinetic parameters did not significantly differ between control and B16-bearing mice. In the other part related to metabolic fate, we showed that among the urinary excretion products, unchanged Mz represented about one third of the eliminated radioactivity. Eight metabolites were separated by HPLC and five identified as degradation products of alkylated glutathione, namely thiodiacetic acid and its sulfoxide, S-carboxymethylcysteine and N-acetyl derivatives of S-carboxymethylcysteine and S-hydroxyethylcysteine.(ABSTRACT TRUNCATED AT 250 WORDS)

Main urinary metabolites of two cysteamine-containing 2-(chloroethyl) nitrosoureas in rats

Urine is the major route of excretion of N'-(2-chloroethyl)-N-[2-(methylsulfinyl)ethyl]-N'-nitrosourea (CMSOEN2), N'-(2-chloroethyl)-N-[2-(methylsulfonyl)ethyl]-N'-nitrosourea (CMSO2EN2), and their metabolites in the rat. Labeling the two compounds with 14C in three different positions facilitated their metabolic study in animals. The 14C-ethyl species were chosen in order to investigate the presence of unchanged compounds and that of the denitrosated forms. With the same 14C label position, we showed that isolated metabolites derived from this part of the molecule were degradation products of alkylated glutathione and/or cysteine. They are common to both CMSOEN2 and CMSO2EN2, namely thiodiacetic acid and its sulfoxide, the sum of which represents about half of urinary radioactivity. N-acetyl carboxymethylcysteine and N-acetyl hydroxyethylcysteine, accounting for approximately 6% to 7% of the eliminated 14C radioactivity, were also characterized. However, four minor metabolites corresponding to less than 10% of the excreted radioactivity remained unidentified. With the [14C]cysteamine and [14C]carbonyl labels related to the isocyanate moiety behavior, we indirectly showed that more than 60% to 70% of the excreted metabolites were carbamoylation products of endogenous substrates. A small amount of free amines, 2-methylsulfinylethylamine and/or 2-methylsulfonylethylamine, representing 15%-16% of the eliminated radioactivity, was also detected. The total data confirm the predominant function of glutathione and/or cysteine in the detoxifying system of the chloroethyl moieties and reveal the unexpected but important role played by carbamoylation reactions in the metabolic fate of the drug isocyanate moieties.

Synthesis and evaluation of new iodine-125 radiopharmaceuticals as potential tracers for malignant melanoma

The synthesis, labeling, and biodistribution of four 125I radiopharmaceuticals designed to localize in melanoma were tested. Uptake in tumors was demonstrated by autoradiography of whole-body sections and quantitated by measurement of radioactivity of selected tissues and tumors using melanoma-bearing mice. N-(2-diethylaminoethyl)-4-iodobenzamide was selected for its highest melanoma uptake: 60 min after IV injection of 6.5% and 4% ID/g, respectively for murine B16 and human melanotic melanoma. Tumor uptake showed the highest values of all analyzed tissues from 6 to 24 hr after injection. High uptake in melanotic tumor tissue with relatively low uptake in blood, muscle, brain, lung, and liver tissue resulted in high tumor/nontumor ratios (at 24 hr for B16, tumor/blood = 37, tumor/brain = 147, tumor/muscle = 95). This agent was compared with iodoamphetamine. Scintigraphic images of the tumor confirmed that external detection of melanoma is possible with this new radiopharmaceutical.

Comparison of monoclonal antibodies to estradiol obtained from structurally different immunogens

The immunization procedure and immunogen characteristics required to optimize the production of anti-steroid monoclonal antibodies have been studied. Five different estradiol-bovine serum albumin conjugates were tested for immunizing mice, as were two different immunization protocols (high and low dose) and the effect of varying the myeloma/spleen cell ratio for cell fusion. Antibody-producing hybridomas, obtained using the spleens of 9 high anti-steroid titre mice, were detected by RIA and EIA. The latter method was less specific than the former for higher affinity anti-estrogen antibodies. All the immunogens elicited anti-estrogen antibodies and the efficiency appeared related to the steroid density on the immunogen rather than the chemical nature of the derivative or the immunization and fusion protocols. Thirty-six anti-estrogen producing hybridomas were detected. Comparison showed that all the immunogens elicited antibodies in a wide range of affinities and specificities. None of the antibodies recognized corticosteroids or progesterone. Cross reactions with testosterone and other estrogens were not clearly related to the nature of the immunogen except that estradiol coupled to the BSA via its carbon 17 yielded antibodies specific for steroids with a non-derivatized phenolic A-ring.

Metabolism of a new radioprotector; S-acetyl-N-glycyl cysteamine. II. Main tissue metabolites in mice bearing EMT6 tumours

1. The major tissue metabolites of the radioprotector S-acetyl-N-glycl cysteamine (I) labelled with 14C on the cysteamine group, were quantified and identified in normal tissues and EMT6 tumours implanted in mice, by chromatographic comparison with authentic reference compounds. 2. In all tissues the radioprotector undergoes rapid deacetylation and hydrolysis leading to the formation of cysteamine, which is the main metabolite involved in radioprotection. A major part of this metabolite is reversibly inactivated by binding to endogenous SH. 3. The differential radioprotection of healthy tissues versus EMT6 tumour is explained both by a lower uptake of radioprotector, and a weaker deacetylation and hydrolysis rate, in the tumour cells.

Metabolism of a new radioprotector; S-acetyl-N-glycyl cysteamine. I. Absorption, distribution and excretion metabolites in mice bearing EMT6 tumours

1. The disposition of S-acetyl-N-glycyl cysteamine (I) labelled with 14C on the cysteamine group (label 1), the glycyl group (label 2) and the acetyl group (label 3) has been studied in mice bearing EMT6 tumours. 2. Label 1 was mainly excreted in urine (63.1% dose in 24 h). Label 2 elimination was both in urine (36.0% dose in 24 h) and in expired air as 14CO2 (12.1% dose in 24 h). Label 3 was essentially eliminated in expired air as 14CO2 (55.4% dose in 24 h). 3. Tissue distribution studies of label 1 and label 2 showed that concentrations in tissues were higher than blood concentration as early as 10 min after administration. Whichever label was used, only little radio-activity was found in EMT6 tumour and brain. 4. Analysis of the urinary elimination products showed the presence of unchanged I and of cystamine, N-acetylcystamine, N-acetyl-S-methyl cysteamine sulphoxide and taurine. I is a prodrug of cysteamine which is released after deacetylation and hydrolysis of the amide bond. A metabolic pathway is proposed for this new radioprotective agent.

Isolation of osteoclasts from Pagetic bone tissue: morphometry and cytochemistry on isolated cells

Giant osteoclasts and other cells were isolated from Pagetic bone tissue using 0.5 mM ethylene diamine tetraacetic acid on bone samples from 8 patients with Paget's disease. The cell suspension contained osteoclasts and osteoblasts as well as some mononuclear cells such as monocytes. The number of nuclei in isolated osteoclasts (33.85 +/- 20.92 nuclei/osteoclast) correlates fairly well (p less than 0.02) with the number of nuclei counted on histologic sections (15.88 +/- 11.80 nuclei/osteoclast) for samples from each patient. Enzyme histochemistry demonstrated acid phosphatase activity in isolated osteoclasts and in mononucleated cells, such as monocytes. Alkaline phosphatase was detected only in osteoblasts while succinate dehydrogenase was observed in osteoclasts, osteoblasts and monocytes. Esterases, such as nonspecific aliesterase and specific naphthol AS-D acetate esterase, were identified in osteoclasts and in macrophages. Inhibition of specific naphthol AS-D acetate esterase in osteoclasts by addition of sodium fluoride suggests that the enzyme could be of monocytic origin.

Murine monoclonal antibody against aldosterone: production, characterization and use for enzymoimmunoassay

Hybridomas secreting monoclonal antibodies to aldosterone were obtained by fusion of myeloma cells and spleen cells from Balb/c mice immunized with aldosterone-3-carboxylmethyloxime-bovine serum albumin. A monoclonal antibody was purified from ascites fluid and characterized. An affinity constant of 1.61 x 10(9) M-1 has been measured and no cross-reactivity with tetrahydroaldosterone (THA), cortisol, cortisone, corticosterone, deoxycorticosterone (DOC), dehydroepiandrosterone (DHA), progesterone and estrone, could be detected. A peroxidase conjugated-antibody (1.5 mole of enzyme per mole of antibody) was obtained and used for microwell enzyme immunoassay and Immun-Blot assay. The high affinity and specificity of this antibody should make the direct determination of aldosterone in biological fluids possible at concentrations as low as 5 x 10(-10) M.

Brain uptake of labelled adiphenine in rats

This study describes the behaviour of a dual labelled drug, adiphenine, in the rat brain. Macroautoradiographies show images of the brain at different times after injection. Some of the tissue metabolites are identified at the brain level and the passage of the blood brain barrier is compared with tritiated water. The obtained data give very interesting indications on the blood brain distribution and on the metabolism at the brain level. Different techniques of high pressure liquid chromatography, macro- and histoautoradiographies allowed us to visualize how the drug is fixed on cerebral structures, giving indications on its mechanism of action. This fat soluble compound freely crosses the normal blood brain barrier and if labelled with the appropriate emittor could be very useful in nuclear medicine to obtain imaging of the brain.

Metabolism of 2-chloroethyl nitrosocarbamoylcystamine by rat liver subcellular fractions

Previously we have shown that a new nitrosourea, 2-chloroethyl nitrosocarbamoylcystamine (CNCC), undergoes an extensive metabolism in the rat. Two pairs of plasma metabolites have been identified. This suggested our hypothesis that the metabolic pathway involves the reduction of the disulfur bridge followed by the methylation and the oxidation of the thiol groups. The two first intermediates, i.e. the unoxidized metabolites, could not be detected in vivo. Hence, to better understand and to confirm the proposed mechanism of biotransformation of CNCC, its in vitro metabolism has been studied. Incubation of CNCC with a rat liver homogenate or a 10,000g supernatant fraction leads to the formation of four pairs of metabolites. Among them we have identified the two first intermediates not found in vivo and the oxidized metabolites. These findings, together with the kinetics data, suggest that reduction, methylation, and oxidation are very rapid enzymatic reactions. We also show that, for completion of the reaction, the incubation mixture had to contain a cytosolic thioreductase, a microsomal and cytosolic S-methyltransferase, a microsomal oxidase, and an NADPH generating system. The sum of the amounts of metabolites found in the organic extratable material is less than the amount of CNCC metabolized. We conclude that the biotransformation of CNCC proceeds from two fast competitive mechanisms operative on both the disulfur and the nitroso groups.

Adiphenine plasma levels and blood-brain barrier crossing in the rat

Adiphenine was administered in 3H-labelled form in doses of 15 mumole/kg intravenously to male Wistar rats. Plasma and brain levels of the unchanged drug were measured. The elimination of the 3H-labelled compound from the plasma was monophasic with a half-life of 13 minutes. The unchanged drug was detectable in the plasma for 30 minutes after the injection. The time course of brain levels of unchanged drug paralleled that found in the plasma with a half-life of 9 to 12 minutes. In all experiments, brain and plasma levels of unchanged adiphenine correlate highly.

Transposed ciliary microtubules in Kartagener's syndrome. A case report with electron microscopy of bronchial and nasal brushings

Report is made of the case of a 44-year-old white woman with Kartagener's syndrome marked by respiratory disorders and repeated serous otitis since infancy. The technique of cell sampling through bronchial and nasal brushings facilitated observation of ciliary structures in electron microscopy. The results revealed a specific anomaly in the organization of the ciliary microtubules. The doublet transposition observed may be associated with ciliary dyskinesia.

Metabolic disposition of 2-chloroethyl nitrosocarbamoylcystamine in rats

The disposition and the metabolism of 2-chloroethyl nitrosocarbamoylcystamine (CNCC), a new antitumor agent, has been studied in rats. For this purpose, three separate labeled species of CNCC have been used. The tissue distribution and the elimination of the radioactivity were determined in animals after gavage with a single dose of each labeled species of CNCC (35 mumol/kg). It was observed, after analysis of plasma taken at timed intervals after administration, that little radioactivity co-chromatographed with the parent compound. These data suggest that CNCC undergoes an important first-pass metabolism, but chromatographic analysis provided evidence for the formation of four main metabolites. These biotransformation products were isolated from pooled plasma extracts of rats treated with 200 mumol/kg of unlabeled CNCC. They were identified by the combined use of mass spectrometry and chromatographic properties. These metabolites are sulfinyl and sulfonyl derivatives arising from the bioreduction of the disulfur bridge of CNCC with subsequent methylation and oxidation. These compounds are potentially active cytostatic agents. The evaluation of their antitumor activity is currently under investigation.

Main metabolites of 1-(2-chloroethyl)-3-[1'-(5'-p-nitrobenzoyl-2',3'-isopropylidene)-alpha, beta-D-ribofuranosyl]-1-nitrosourea and 1-(2-chloroethyl)-3-(2',3', 4'-tri-O-acetyl-alpha, beta-D-ribopyranosyl)-1-nitrosourea in rats

The metabolism of two glycosylnitrosoureas, 1-(2-chloroethyl)-3-[1'-(5'-p-nitrobenzoyl-2',3'-isopropylidene)-alpha, beta-D-ribofuranosyl]-1-nitrosourea (RFCNU) and 1-(2-chloroethyl)-3-(2',3',4'-tri-O-acetyl-alpha, beta-D-ribopyranosyl)-1-nitrosourea (RPCNU), has been investigated in the rat. With the label on the carboxyl moiety of RFCNU, we have shown that hydrolysis of the 4-nitrobenzoyl ester occurred to a large extent in vivo; 4-nitrobenzoic acid and its glucuronide were the major urinary metabolites. Two other minor metabolites and their glucuronides were identified as 4-aminobenzoic acid and 4-acetamidobenzoic acid. With the label on the chloroethyl moieties of RFCNU and RPCNU, we have shown that chloroethanol was a major degradation product of this alkylating part of the molecule. The concentration of chloroethanol in plasma vs. time has been determined. In urine, four metabolites derived from alkylated glutathione, namely thiodiacetic acid and its sulfoxide, N-acetylcarboxymethylcysteine, and N-acetylhydroxyethylcysteine, have been identified.

Effect of chloroquine on thyroliberin interaction with clonal rat prolactin cells. Cytochemical correlates

The lysosomotropic agent, chloroquine, has been used to investigate the implication of lysosomal activity and membrane traffic in TRH binding, TRH internalization and TRH-induced stimulation of prolactin secretion in a rat prolactin cell line (GH3/B6). Chloroquine by itself does not affect cell number, cell protein and basal prolactin secretion. It does not alter TRH binding and internalization as well as both effects of TRH on the stimulation of prolactin secretion, i.e., prolactin release and prolactin production. In contrast, chloroquine partially inhibits the spontaneous dissociation of (3H)TRH from cells previously loaded with (3H)TRH and reduces prolactin release following TRH withdrawal. In addition the kinetic pattern of the TRH dissociation is modified in a manner which suggests that TRH is bound to different intracellular compartments. Chloroquine, nevertheless, does not alter the TRH-induced down regulation of (3H)TRH binding sites. Electron microscopic observations and acid phosphatases localization reveal that chloroquine elicits a disorganization of the Golgi zone and accumulation of membrane whorls within large vacuoles. This suggests that the effects of chloroquine on TRH interaction with GH3 cells may be mediated by an inhibition of membrane recycling.

Disposition and metabolism in 1-(2-chloroethyl)-3-(2',3',4'-tri-o-acetyl, ribopyranosyl)-1-nitrosourea in rats

The antineoplastic activity in animals of 1-(2-chloroethyl)-3-(2',3',4'-tri-O-acetyl, ribopyranosyl)-1-nitrosourea (RPCNU) has been widely demonstrated. The present study deals with the disposition and the metabolism of three 14C-labeled species of RPCNU. The chemical plasma half-life of the drug was less than 5 min. Within the first min after injections, most of the radioactivity derived from ethyl-14C groups were recovered as volatile products. Among these, 2-chloroethanol was identified as a main component. Analysis of labeled species in urine after administration of [ethyl-14C]RPCNU showed that thiodiacetic acid and its sulfoxide were major metabolites of RPCNU (62% of the urinary radioactivity). Traces of N-acetylcarboxymethyl- and N-acetylhydroxyethylcysteine) were also detected. The only labeled species concentrating in particular tissues was that carrying the chloroethyl moiety. Uptake to high levels of [ethyl-14C]RPCNU did occur in liver, kidney, pancreas, thymus, and Harder's gland.