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[en] Purpose: To determine whether MR bone marrow findings in Gaucher patients may help to identify patients at high risk of developing severe Gaucher bone complications exemplified by avascular necrosis (AVN) of the femoral head. Materials and Methods: MR images were obtained in 63 Type I Gaucher patients through a standard protocol using coronal T1 and T2-weighted sequences of the lower extremities. The location and extent of infiltrated marrow was established using a semi-quantitative MRI scoring method (Duesseldorf Gaucher score, DGS) and the morphological pattern of bone marrow involvement determined (whether homogeneous type A or non-homogeneous type B). The active marrow process with bone edema and AVN of the femoral head were also analyzed. Results: Bone marrow involvement was observed in femoral sites more than in tibial sites. A high DGS was significantly correlated with type B morphology and femoral AVN (both p < 0.0001). Splenectomized patients showed a significantly higher Duesseldorf Gaucher score and type B morphology than non-splenectomized patients (both p < 0.05). AVN was seen in 46 % of patients with type B morphology versus 3 % in type A morphology (p < 0.0001). DGS and morphology of bone marrow involvement were not significantly correlated with active marrow processes. Conclusion: Type B marrow morphology and extensive marrow packing were significantly associated with AVN of the femoral head (both p < 0.0001). These patterns are considered predictive and may be employed in a disease management context to alert physicians to the need for urgent therapeutic measures. (orig.)
[en] Acquired aplastic anaemia is one of the important causes of pancytopenia. This study was conducted to observe the mode of presentation of acquired aplastic anaemia and to find out its possible etiological factors. Methods: It is a hospital based descriptive study of 100 patients of acquired aplastic anaemia. Results: Out of 100 patients 60 were male and 40 female. Majority (44%) of the patients were between 12 - 20 years of age. Patient presented with variable symptoms majority (40%) with fever. Most of the patients had haemoglobin levels between 4 - 6 gm/dl. (53%). Seventy percent of the cases had no obvious cause, while in 30% some known causative factors were found. Chloramphenicol was found to be the most common causative drug. Mortality was 35%. Thirty patients were partially treated and 15 were lost to follow up. Twenty patients showed improvement with treatment. Conclusions: Acquired aplastic anaemia is common among males and more prevalent in younger age group. It is idiopathic in 70% cases while 30% had some cause. It has very high mortality. Doctors need to keep in mind this fatal condition in patients presenting with anaemia and should properly investigate before prescribing antibiotics and haematinics. (author)
[en] In vitro effects of OK-432 (polysaccharide extract of Streptococcus haemolyticus) on irradiated mouse bone marrow cells are examined. Bone marrow cells of BDF1 mouse (1 x 106 cells/ml) were incubated with alpha medium, 2% fetal calf serum and OK-432 in a CO2 incubator at 37 degrees C for 24, 48 and 72 h, respectively. After centrifugation, each supernatant was collected and used for conditioned medium in a CFU-GM assay: Changes in CFU-GM as a function of incubation time and OK-432 dose were examined; changes of CFU-GM according to various doses of OK-432 were examined in two mouse strains, BDF1 and BALB/c mouse; changes in the protective effect of OK-432 in terms of CFU-GM as a function of administration timing of OK-432 in relation to irradiation. As a radiation source, 137Cs at a dose rate of 500 cGy/min was used. The CFU-GM decreased with the incubation time when OK-432 was not administered, while it significantly increased with incubation time when OK-432 was added at 0.5 and 1.0 KE/ml at 48-72 h of incubation. The former showed marked increase at 48-72 h of incubation. CFU-GM of BDF1 mouse was always higher than that of BALB/c mouse for any dose of OK-432. CFU-GM per femur according to the timing of administration of OK-432 from 24 h before to 24 h after irradiation showed 10299 ± 2300 (24 h before), 10783 ± 2463 (3 h before), 10045 ± 1501 (immediately after), 8504 ± 1188 (3 h after), 4898 ± 1212 (6 h after), 1214 ± 736 (12 h after) and 181 ± 113 (24 h after irradiation), respectively. OK-432 stimulates cultures mouse bone marrow cells to produce GM-CSF in vitro by direct contact action. This direct stimulating action of OK-432 on GM-CSF production of bone marrow cells can be kept from 24 h before to at least 3 h after irradiation. 6 refs., 4 figs
[en] Evaluation of radiation dose rate and fractionation effects on clonogenic myeloma cells was carried out. The radiosensitivity of clonogenic myeloma cells was evaluated for seven human myeloma cell lines. The lines were maintained in liquid suspension culture. Following radiation, cells were plated in semisolid medium using methylcellulose as viscous support. Radiation doses up to 12 Gy were delivered at dose rates of 0.05 and 0.5 Gy/min by a 60Co source. Each total dose was administered either as a single dose or in multiple fractions of 2 Gy. The data were analyzed according to the linear quadratic and multi target model of irradiation. Clonogenic progenitors of the seven myeloma cell lines differed in their radiosensitivity as measured by multiple parameters. The differences were mainly observed at low dose. The most effective cytoreduction was seen when radiation was administered in a single fraction at high dose rate. The cytoreductive effect on clonogenic myeloma cells was compared for clinically practiced total body irradiation (TBI) schedules delivered either in a single or in multiple fractions without causing significant pulmonary toxicity. The administration of 12 Gy delivered in six fractions of 2 Gy resulted in a superior reduction of clonogenic cells compared to a single fraction of 5 Gy. The preparation of bone marrow transplant recipients with multiple myeloma using fractionated radiation with a total dose of 12 Gy appears to afford better ablation than a single dose of 5 Gy while maintaining a low incidence of pulmonary toxicity. 20 refs., 4 figs., 4 tabs
[en] The effects of feeding irradiated wheat in mice on bone marrow and testis chromosomes, germ cell numbers and dominant lethal mutations were investigated. Feeding of freshly irradiated wheat resulted in significantly increased incidence of polyploid cells in bone marrow, aneuploid cells in testis, reduction in number of spermatogonia of types A, B and resting primary spermatocytes as well as a higher mutagenic index. Such a response was not observed when mice were fed stored irradiated wheat. Also there was no difference between the mice fed un-irradiated wheat and stored irradiated wheat. (author)
[en] LEC strain rats, which have been known to develop hereditarily spontaneous fulminant hepatitis 4 to 5 months after birth, are highly sensitive to whole-body X-irradiation when compared to WKAH strain rats. The present results showed that the frequencies of all types of chromosome aberrations induced by X-irradiation in the bone marrow cells of LEC rats were approximately 2- to 3-fold higher than those of WKAH rats, though no significant difference was observed in the frequency of spontaneous chromosome aberrations between LEC and WKAH rats
[en] The molecular mechanisms that transduce the osteoblast response to physical forces in the bone microenvironment are poorly understood. In this paper, we used genetic and pharmacological experiments to determine whether the polycystins PC1 and PC2 (encoded by Pkd1 and Pkd2) and the transcriptional coactivator TAZ form a mechanosensing complex in osteoblasts. Compound-heterozygous mice lacking 1 copy of Pkd1 and Taz exhibited additive decrements in bone mass, impaired osteoblast-mediated bone formation, and enhanced bone marrow fat accumulation. Bone marrow stromal cells and osteoblasts derived from these mice showed impaired osteoblastogenesis and enhanced adipogenesis. Increased extracellular matrix stiffness and application of mechanical stretch to multipotent mesenchymal cells stimulated the nuclear translocation of the PC1 C-terminal tail/TAZ (PC1-CTT/TAZ) complex, leading to increased runt-related transcription factor 2–mediated (Runx2-mediated) osteogenic and decreased PPARγ-dependent adipogenic gene expression. Using structure-based virtual screening, we identified a compound predicted to bind to PC2 in the PC1:PC2 C-terminal tail region with helix:helix interaction. This molecule stimulated polycystin- and TAZ-dependent osteoblastogenesis and inhibited adipogenesis. Therefore, we show that polycystins and TAZ integrate at the molecular level to reciprocally regulate osteoblast and adipocyte differentiation, indicating that the polycystins/TAZ complex may be a potential therapeutic target to increase bone mass.
[en] Thrombocytopenia is an important cause of hemorrhage and death after radiation injury, but the pathogenesis of radiation-induced thrombocytopenia has not been fully characterized. Here, we investigated the influence of radiation-induced endothelial cell injury on platelet regeneration. We found that human umbilical vein endothelial cells (HUVECs) underwent a high rate of apoptosis, accompanied by a significant reduction in the expression of vascular endothelial growth factor (VEGF) at 96 h after radiation. Subsequent investigations revealed that radiation injury lowered the ability of HUVECs to attract migrating megakaryocytes (MKs). Moreover, the adhesion of MKs to HUVECs was markedly reduced when HUVECs were exposed to radiation, accompanied by a decreased production of platelets by MKs. In vivo study showed that VEGF treatment significantly promoted the migration of MKs into the vascular niche and accelerated platelet recovery in irradiated mice. Our studies demonstrate that endothelial cell injury contributes to the slow recovery of platelets after radiation, which provides a deeper insight into the pathogenesis of thrombocytopenia induced by radiation.