Amount Of Bone Marrow Research Articles

TNC/Kg and CD34+/Kg Cell Dose Impact on Patient Engraftment after Allogeneic Transplant with Conventional Bone Marrow; Better Predictability of Graft Content Needed

Introduction: Bone marrow (BM) harvested from a related (RD) or unrelated donor (URD) remains a viable graft source for patients (pts) receiving an allogeneic hematopoietic stem cell transplant (allo-HCT). However guidance on minimum TNC/kg & CD34+/kg thresholds to optimize engraftment & a method to best predict graft content are needed. Methods: All BM products (prdcts) harvested between 1/1/2016 to 6/30/2023 for adult & pediatric (ped) pts were studied (n= 261). Pt, donor, & BM prdct characteristics were collected. For each BM prdct, pre-processing (pre-proc) data was obtained to determine a median pre-proc TNC, TNC/mL, CD34+/mL, and CD34+/TNC % of all BM prdcts & infused TNC & CD34+ content was also recorded. Pt neutrophil (Neutr) & platelet (Plt) engraftment data was collected with Neutr engraftment defined as the first of 3 consecutive days of an absolute neutr count ≥ 500 x 10^3/μl. Plt engraftment was defined as ≥ 20K/μl plts & transfusion independence for ≥ 7 days. Univariable & multivariable analyses (MVAs) using the Fine and Gray model were performed to assess impact of infused TNC/kg (MVA1), CD34+/kg (MVA2), and CD34+/TNC % (MVA3) of conventional BM prdcts on Neutr (n eval pts = 239) & Plt engraftment (n eval pts = 238). The National Marrow Donor Program's (NMDP) provided estimate for median TNC/mL of BM (0.183 x 10^8) was used w/ donor weight (wt), the NMDP maximum (max) allowable amount of BM (20mL per donor kg), & a standard max BM volume request (1500mL) to calculate an expected pre-proc TNC for all BM prdcts. The expected TNC for small ped pts was limited to (15 * pt wt) to ensure a TNC/kg cell dose of ≤ 15 x 10^8. An expected pre-proc CD34+ for each BM prdct was then calculated by expected TNC x CD34+/TNC % of all BM prdcts on study. An expectation accuracy (EA) % for both TNC & CD34+ was calculated for each BM prdct (expected / actual pre-proc values observed by our center). TNC & CD34+ EA % of BM prdcts collected by other domestic & international centers were analyzed. Results: 261 BM prdcts from 259 donors for 258 pts were studied. The BM prdcts had the following pre-proc medians: TNC/mL of 0.136 x 10^8, CD34+/mL of 0.124 x 10^6, & CD34+/TNC % of 0.96. MSKCC harvested 141 (54%) of the BM prdcts and the rest were facilitated by the NMDP: 71 (27%) from 26 domestic centers and 49 (19%) from 28 international centers. The cumulative incidence of Neutr engraftment was 96% (95% CI 92, 98%) by days +30 and +100 after allo-HCT and for Plts it was 48% (95% CI 42,54%) and 91% (95% CI 87,94%) respectively. Table 1 shows the MVA results testing TNC/kg (MVA1), CD34+/kg (MVA2), CD34+/TNC % (MVA3) & engraftment after allo-HCT w/ conventional BM, indicating Neutr & Plt engraftment is impacted by TNC/kg and CD34+/kg cell dose but not by CD34+/TNC %. In all 3 MVA models, associations were observed for pt diagnosis [SAA w/ better Plt engraftment vs. ref grp], donor type (≤ 7/8 URD or haploidentical RD w/ worse Neutr & Plt engraftment vs. ref grp), donor ABO incompatibility (Minor w/ better Plt engraftment vs. ref grp), and infusion type [cryopreserved (cryo'ed)/thawed w/ worse Neutr engraftment vs. fresh]. The expectation accuracy (EA) analysis (Wilcoxon rank-sum test) of pre-proc TNC & CD34+ is seen in Table 2. The median expected pre-proc TNC (274) & CD34+ (264) of BM prdcts received from domestic centers & international centers were the same. However BM prdcts from international centers had a lower median actual pre-proc TNC (192) & CD34+ (162), a lower median TNC EA of 74% (vs. 89% for dom centers, p=0.008), & a lower median CD34+ EA of 63% (vs. 93% for dom centers, p<0.001). All BM prdcts combined (n = 120) had a median TNC EA of 83% & a median CD34+ EA of 76%. Conclusions: This large analysis suggests BM products with a TNC/kg > 2.0 x 10^8 and a CD34+/kg > 2.0 x10^6 were associated with better Neutr & Plt engraftment, as was allo-HCT with an HLA-matched donor. Cryo'ed products were associated with worse Neutr but not Plt engraftment, while SAA & having a BM graft from a donor with a minor ABO incompatibility were associated with better Plt engraftment. The expectation accuracy analysis suggests BM graft content is often not meeting expectations, highlighting a need for updated guidance on expectations of BM graft content. An update to NMDP's guidance on estimated TNC/mL of BM or analysis and provision of additional data (e.g., median pre-proc CD34+/mL or CD34+/TNC %) could allow centers to better anticipate TNC & CD34+ BM graft content and help guide donor & graft selection.

The Analysis of Fixed Final State Optimal Control in Bilinear System Applied to Bone Marrow by Cell-Cycle Specific (CCS) Chemotherapy

The research conducted by Fister & Panetta shown an optimal control model of bone marrow cells against Cell Cycle Specific chemotherapy drugs. The model used was a bilinear system model. Fister & Panetta research has proved existence, uniqueness, and characteristics of optimal control (the chemotherapy effect). However, by using this model, the amount of bone marrow at the final time could achieve less than 50 percent from the amount of bone marrow before given treatment. This could harm patients because the lack of bone marrow cells made the number of leukocytes declining and patients will experience leukemia. This research would examine the optimal control of a bilinear system that applied to fixed final state. It will be used to determine the length of optimal time in administering chemotherapy and kept bone marrow cells on the allowed level at the same time. Before simulation conducted, this paper shows that the system could be controlled by using a theory of Lie Algebra. Afterward, it shows the characteristics of optimal control. Based on the simulation, it indicates that strong chemotherapy drug given in a short time frame is the most optimal condition to keep bone marrow cells spine on the allowed level but still could put playing an effective treatment. It gives preference of the weight of treatment for keeping bone marrow cells. The result of chemotherapy’s effect (u) is not able to reach the maximum value. On the other words, it needs to make adjustments of medicine’s dosage to satisfy the final treatment condition e.g. the number of bone marrow cells should be at the allowed level.

A simple one-tube assay for immunophenotypical quantification of leukemic stem cells in acute myeloid leukemia.

Relapses after initial successful treatment in acute myeloid leukemia are thought to originate from the outgrowth of leukemic stem cells. Their flow cytometrically assessed frequency is of importance for relapse prediction and is therefore assumed to be implemented in future risk group profiling. Since current detection methods are complex, time- and bone marrow consuming (multiple-tubes approach), it would be advantageous to have a broadly applicable approach that enables to quantify leukemia stem cells both at diagnosis and follow-up. We compared 15 markers in 131 patients concerning their prevalence, usefulness and stability in CD34(+)CD38(-) leukemic stem cell detection in healthy controls, acute myeloid leukemia diagnosis and follow-up samples. Ultimately, we designed a single 8-color detection tube including common markers CD45, CD34 and CD38, and specific markers CD45RA, CD123, CD33, CD44 and a marker cocktail (CLL-1/TIM-3/CD7/CD11b/CD22/CD56) in one fluorescence channel. Validation analyses in 31 patients showed that the single tube approach was as good as the multiple-tube approach. Our approach requires the least possible amounts of bone marrow, and is suitable for multi-institutional studies. Moreover, it enables detection of leukemic stem cells both at time of diagnosis and follow-up, thereby including initially low-frequency populations emerging under therapy pressure.

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Purpose. To evaluate 12 patients with delayed or nonunion of bones treated with bone marrow injections. Methods. 6 men and 6 women aged 15 to 70 (mean, 45) years underwent bone marrow injections for delayed union (n=2) or atrophic non-union (n=10) of the ulna (n=6), femur (n=3), humerus (n=2), or metacarpal (n=1). Bone marrow was aspirated from the anterior iliac crest and injected to the delayed and non-union sites. Two injections were given for children and adolescents, and 3 for adults. The interval between the injections was 6 to 8 weeks. The amount of bone marrow injected was 30 to 40 ml for long bones and 20 ml for metacarpals. Results. Ten of the 12 delayed or non-union of bones healed after bone marrow injections. The mean time for callus formation was 5.8 (range, 3–10) weeks, for clinical union was 7 (range, 4–12) weeks, and for radiological union was 16 (range, 10–24) weeks. Conclusion. Multiple injections of low-volume bone marrow can be used for treatment of delayed or non-union of bones.

Ridge preservation with the use of deproteinized bovine bone mineral

The aim was to examine the tissue composition of extraction sockets that had been grafted with deproteinized bovine bone mineral and allowed to heal for 6months. Twenty-five subjects with one tooth each scheduled for extraction and replacement with dental implants were recruited. The assigned teeth were carefully removed. The site/patient was thereafter allocated to a test or a control group. In the test group patients, Bio-Oss(®) Collagen was placed to fill the fresh extraction socket while in the controls no grafting was performed. After about 6months of healing, a biopsy was sampled from the center of the extraction site. The specimens were decalcified, embedded in paraffin, sectioned, and stained in HTX. The proportions occupied by mineralized bone, osteoid, bone marrow, fibrous tissue, and Bio-Oss(®) particles were determined by morphometric point counting. Mineralized bone made up 57.4±12.4% of the control sites (C) and 48.9±8.5% of the T1 sites (graft material not included). The amount of bone marrow (C: 7.1±6.1%, T1: 2.1±3.1%) and osteoid (C: 7.3±4.9%, T1: 1.9±2.1%) was about five times greater in the control than in the test sites. Fibrous tissue comprised 23.1±16.3% (C) and 40.0±11.9% (T1). I n the T2 sites (graft material included), the percentage mineralized bone was 39.9±8.6 while the proportions of bone marrow and osteoid were 1.8±2.5% and 1.6±1.8%. Fibrous tissue occupied 32.4±9.2% and Bio-Oss(®) particles 19.0±6.5% of the T2 sites. Placement of the biomaterial in the fresh extraction socket retarded healing. The Bio-Oss(®) particles were not resorbed but became surrounded by new bone. This may explain why grafted extraction sites may fail to undergo dimensional change.

Bone Progenitors Produced by Direct Osteogenic Differentiation of the Unprocessed Bone Marrow Demonstrate High Osteogenic PotentialIn VitroandIn Vivo

Tissue-engineered bone grafts seeded with mesenchymal stem cells (MSCs) have been sought as a replacement for bone grafts currently used for bone repair. For production of osteogenic constructs, MSCs are isolated from bone marrow (BM) or other tissues, expanded in culture, then trypsinized, and seeded on a scaffold. Predifferentiation of seeded cells is often desired. We describe here bone progenitor cells (BPCs) obtained by direct osteogenic differentiation of unprocessed BM bypassing isolation of MSCs. Human BM aspirates were incubated for 2 weeks with a commonly used osteogenic medium (OM), except no fetal calf serum, serum substitutes, or growth factors were added, because responding stem and/or progenitor cells were present in the BM milieu. The adherent cells remaining after the culture medium and residual BM were washed out, expressed high levels of bone-specific alkaline phosphatase (ALP) on their surface, demonstrated high ALP activity, were capable of mineralization of the intercellular space, and expressed genes associated with osteogenesis. These parameters in BPCs were similar and even at higher levels compared to MSCs subjected to osteogenic differentiation for 2 weeks. The yield of BPCs per 1 mL BM was 0.71±0.39×106. In comparison, the yield of MSCs produced by adhesion of mononuclear cells derived from the same amount of BM and cultured in a commercial growth medium for 2 weeks was 0.3±0.17×106. When a scaffold was added to the BM-OM mixture, and the mixture was cultured in a simple rotational bioreactor; the resulting BPCs were obtained already seeded on the scaffold. BPCs seeded on scaffolds were capable of proliferation for at least 6 weeks, keeping high levels of ALP activity, expressing osteogenic genes, and mineralizing the scaffolds. Autologous rat BPCs seeded on various scaffolds were transplanted into critical-size calvarial defects. Six weeks after transplantation of polylactic acid/polyglycolic acid scaffolds, 76.1%±18.3% of the defects were filled with a new bone, compared to 37.9%±28.4% in the contralateral defects transplanted with the scaffolds without cells.

Dendritic cells: Transcriptional control of plasmacytoid dendritic cell development by E2‐2

Dendritic cells: Transcriptional control of plasmacytoid dendritic cell development by E2-2

Adipose stem cells as a clinically available and effective source of adult stem cell therapy.

The greatest advantage of adipose-derived stem cells (ASCs) over other types of adult stem cells is its large number when we harvest primarily. The number of ASCs within adipose tissue reaches more than hundreds of times compared with BMSCs contained in the same amount of bone marrow. The major role of 'regenerative medicine' in 21st century is based on cell therapy and ASC is going to take the core position. It is important to know the characteristics of ASCs for successful clinical application. There are several unique features of ASCs which is known common characteristic of mesenchymal stem cells (MSCs). Cellular plasticity is one of the most important features of ASCs as in other adult stem cells and the cells also have a special function of immune modulation and immunosuppression. Strong angiogenic potential is another important nature of ASCs. In many reports, ASCs are known not only to be differentiated into osteoblasts, chondrocytes, vascular endothelial cells, but also to be cardiomyocytes and neuronal cells. In conclusion, the new knowledge of ASCs is going to impact on the regenerative medicine. To take the advantage of this new type of cells and utilize the cells, we need to understand the function of ASCs and future possibilities of ASCs. We plastic surgeons continue to stimulate the our curiosity and creativity, as well as our clinical inspiration.

Cells enriched in markers of neural tissue-committed stem cells reside in the bone marrow and are mobilized into the peripheral blood following stroke

The concept that bone marrow (BM)-derived cells participate in neural regeneration remains highly controversial and the identity of the specific cell type(s) involved remains unknown. We recently reported that the BM contains a highly mobile population of CXCR4+ cells that express mRNA for various markers of early tissue-committed stem cells (TCSCs), including neural TCSCs. Here, we report that these cells not only express neural lineage markers (beta-III-tubulin, Nestin, NeuN, and GFAP), but more importantly form neurospheres in vitro. These neural TCSCs are present in significant amounts in BM harvested from young mice but their abundance and responsiveness to gradients of motomorphogens, such as SDF-1, HGF, and LIF, decreases with age. FACS analysis, combined with analysis of neural markers at the mRNA and protein levels, revealed that these cells reside in the nonhematopoietic CXCR4+/Sca-1+/lin-/CD45 BM mononuclear cell fraction. Neural TCSCs are mobilized into the peripheral-blood following stroke and chemoattracted to the damaged neural tissue in an SDF-1-CXCR4-, HGF-c-Met-, and LIF-LIF-R-dependent manner. Based on these data, we hypothesize that the postnatal BM harbors a nonhematopoietic population of cells that express markers of neural TCSCs that may account for the beneficial effects of BM-derived cells in neural regeneration.

Cells Expressing Early Cardiac Markers Reside in the Bone Marrow and Are Mobilized Into the Peripheral Blood After Myocardial Infarction

The concept that bone marrow (BM)-derived cells participate in cardiac regeneration remains highly controversial and the identity of the specific cell type(s) involved remains unknown. In this study, we report that the postnatal BM contains a mobile pool of cells that express early cardiac lineage markers (Nkx2.5/Csx, GATA-4, and MEF2C). These cells are present in significant amounts in BM harvested from young mice but their abundance decreases with age; in addition, the responsiveness of these cells to gradients of motomorphogens SDF-1, HGF, and LIF changes with age. FACS analysis, combined with analysis of early cardiac markers at the mRNA and protein levels, revealed that cells expressing these markers reside in the nonadherent, nonhematopoietic CXCR4+/Sca-1+/lin-/CD45- mononuclear cell (MNC) fraction in mice and in the CXCR4+/CD34+/AC133+/CD45- BMMNC fraction in humans. These cells are mobilized into the peripheral blood after myocardial infarction and chemoattracted to the infarcted myocardium in an SDF-1-CXCR4-, HGF-c-Met-, and LIF-LIF-R-dependent manner. To our knowledge, this is the first demonstration that the postnatal BM harbors a nonhematopoietic population of cells that express markers for cardiac differentiation. We propose that these potential cardiac progenitors may account for the myocardial regenerative effects of BM. The present findings provide a novel paradigm that could reconcile current controversies and a rationale for investigating the use of BM-derived cardiac progenitors for myocardial regeneration.

Evidence That CXCR4+ Neural Tissue-Committed Stem Cells (TCSC) Reside/Hide out in the Bone Marrow and Are Mobilized into the Peripheral Blood during Stroke.

Several recent studies in animals as well as humans support the notion that bone marrow (BM)-derived cells participate in brain regeneration. However, the identity of the specific cell type responsible for regeneration remains unknown. Recent work from our laboratory revealed that BM contains a highly mobile population of CXCR4+ cells that express mRNA for various markers of early tissue-committed stem cells (TCSC) and which are distinct from hematopoietic stem cells (HSC) (Leukemia 2004: 18;29–40). In this study we investigated whether BM also contains a mobile pool of TCSC destined to differentiate into neural cells. The TCSC were isolated from bone marrow by employing chemotactic gradient to SDF-1 or by FACS sorting and subsequently evaluated for a presence of early neural markers by i) real time RT-PCR analysis (nestin, GFAP), ii) immunohistochemical staining (nestin, beta-III tubulin), and iii) by employing functional in vitro assays to study ability of these purified cells to form neurospheres. Our data demonstrate that TCSC for neural cells (i) are present in significant amounts in BM harvested from young (1–2 month-old) while being barely detectable in older (1-year-old) mice; ii) reside in populations of murine BM-derived non-adherent non-hematopoietic Sca-1+ CD45− cells and in population of human CXCR4+ CD34+ AC133+ CD45− BMMNC, iii) are mobilized from BM into peripheral blood (PB) during pharmacological mobilization or 24 hours after Bengal-rose induced stroke in mice; iv) SDF-1 is highly upregulated in damaged brain tissue, and v) TCSC are chemoattracted for potential brain regeneration in SDF-1-CXCR4, dependent manner. Thus, we conclude that bone marrow is a potential source of TCSC for brain repair and since purified CD45+ HSC neither express neuronal markers nor differentiate in vitro into neurospheres, we provide for a first time evidence that neural TCSC residing in bone marrow but not “plastic” HSC account for neural differentiation of BM-derived cells. Furthermore, our observation that the number of marrow derived mobile/circulating neural TCSC is the highest in BM of young animals and decreases with age provides a novel insight into aging and may explain why the brain regeneration process becomes less effective in older individuals. Finally, these observations provide rationale for further studies aimed at optimizing therapeutic brain regeneration by BM-derived neural TCSC.

Comparing Levels of Subsistence Stress amongst Norse Settlers in Iceland and Greenland using Levels of Bone Fat Exploitation as an Indicator

The background to the Icelandic and Greenlandic sites under investigation is outlined and prior work on the Norse economies of the two islands is discussed. The importance of fat in the diet and the use of levels of bone marrow and grease exploitation as an indicator of subsistence stress are explained. The methodology for establishing levels of bone fat exploitation is outlined. This methodology involves the detailed study of fragmentation levels of different types of bone, study of bone fracture types and many other taphonomic indicators. The results of the study are described and discussed. On Greenland, the Norse inhabitants exploited almost all available fat from land mammal bones, leaving only the ribs. It is argued that this indicates a severe level of subsistence stress amongst the Greenlanders that is most likely related to a seasonal dearth in resources. On Iceland, whilst a certain amount of bone marrow is almost certainly exploited, the settlers appear to almost totally ignore the potential to exploit bone grease. This is likely to be indicative of a much more healthy subsistence economy than on Greenland. These results are discussed in relation to differing climate, availability of good soil, fishing practices and seasonal rounds.

Evaluation of two biodegradable polymeric systems as substrates for bone tissue engineering.

The aim of this study was to evaluate two biodegradable polymeric systems as scaffolds for bone tissue engineering. Rat bone marrow cells were seeded and cultured for 1 week on two biodegradable porous polymeric systems, one composed of poly(ethylene glycol)-terephthalate/poly(butylene terephthalate) (PEGT/PBT) and the other composed of cornstarch blended with poly(epsilon-caprolactone) (SPCL). Porous hydroxyapatite granules were used as controls. The ability of cells to proliferate and form extracellular matrix on these scaffolds was assessed by a DNA quantification assay and by scanning electron microscopy examination; their osteogenic differentiation was screened by the expression of alkaline phosphatase. In addition, the in vivo osteogenic potential of the engineered constructs was evaluated through ectopic implantation in a nude mouse model. Results revealed that cells were able to proliferate, differentiate, and form extracellular matrix on all materials tested. Moreover, all constructs induced abundant formation of bone and bone marrow after 4 weeks of implantation. The extent of osteogenesis (approximately 30% of void volume) was similar in all types of implants. However, the amount of bone marrow and the degree of bone contact were higher on HA scaffolds, indicating that the polymers still need to be modulated for higher osteoconductive capacity. Nevertheless, the findings suggest that both PEGT/PBT and SPCL systems are excellent candidates to be used as scaffolds for a cell therapy approach in the treatment of bone defects.

In vivo involvement of heparan sulfate proteoglycan in the bioavailability, internalization, and catabolism of exogenous basic fibroblast growth factor.

The in vivo bioavailability of exogenous fibroblast growth factor 2 (FGF2) was studied after i.v. injection of uniformly 14C-labeled FGF2 into young rats. 14C-FGF2 was rapidly accumulated in almost all solid organs within 5 min. After 30 min, more than 65% of FGF2 was retained in liver, 4.5% in kidneys, 1.2% in spleen, 0.15% in adrenal glands, and trace amounts in bone marrow, eyes, lungs, and heart. Suborgan distribution of 14C-FGF2 showed that for kidneys and adrenal glands, the labeling was mainly concentrated in the cortical zone. Incubation of organ sections with 2 M NaCl or heparin eluted all the radioactivity, indicating that labeling was due to FGF2-heparan sulfate proteoglycan (HSPG) interactions. Electrophoretic analysis show only native 14C-FGF2 in the blood and extracellular matrix; however, FGF2 is continuously catabolized in solid organs, indicating that all participate in the clearance of FGF2 by cellular internalization and subsequent catabolism. All FGF2 catabolic fragments bound heparin, demonstrating the preservation of their HSPG-binding site during the in vivo intracellular catabolism of FGF2. Analysis of the high-affinity receptors of FGF2 (FGFR-1 and FGFR-3) and the mitogen-activated protein kinase did not show any increase in either FGFR tyrosine phosphorylation or in mitogen-activated protein kinase activation. This study shows for the first time that exogenous FGF2 is cleared by HSPG cellular internalization and catabolism without inducing the activation of FGFRs within at least five organs in vivo, which strongly suggests that the HSPG-dependent internalization and catabolism pathway may control the in vivo bioavailability of FGF2.

Bone augmentation at titanium implants using autologous bone grafts and a bioresorbable barrier. An experimental study in the rabbit tibia.

The aim of the present investigation was to compare the effect of using autologous bone particles covered with a bioresorbable matrix barrier with the use of bone particles alone on bone augmentation at titanium implants installed in the rabbit tibia. Two Brånemark System implants, one in each tibia, were inserted in each of 9 rabbits in such a way that 5 threads were not covered with bone. Autologous bone particles were harvested from the skull and placed over the exposed implant surfaces on each tibia. The bone graft on one tibia was covered with a Guidor Matrix Barrier, while the bone graft on the other tibia served as a control. After a healing period of 12 weeks, the animals were sacrificed and specimens taken for histomorphometrical analyses. The analyses showed that a significantly larger volume of augmented bone tissue had formed at the test sites. There were, however, no differences in the amount of mineralized bone. In fact, the difference in tissue volume was due to an increased amount of bone marrow at the test sites. The degree of mineralized bone to implant contact as well as the degree of mineralized bone within the threads at the test implants were similar to that at the controls. In conclusion, it was found that the coverage of particulate autologous bone grafts with a bioresorbable barrier resulted in a larger volume of augmented bone than the use of bone grafts not covered with a barrier.

The Phenomenology and Possible Mechanisms of a New Experimental Method for Accelerating Postirradiation Restoration of Hemopoietic Stem Cell Potential

Extraction of bone marrow from one or several bones immediately after irradiation, with or without subsequent incubation for a short period under suitable conditions, and subsequent reimplantation into the same organism can reduce the lethal effect of irradiation in a number of species. Extraction plus a period of incubation is referred to as the reimplantation method. The effectiveness is roughly relative to the amount of bone marrow extracted and transplanted. This effect has been demonstrated by assays of 30-45-day survival and of hemopoietic stem cell potential. The effectiveness of the reimplantation method has been tested in a dose range of 6.5 to 8.5 Gy and was found to be 1.2-1.06 in terms of dose reduction factors assayed by bone marrow row cellularity 9 days after exposure and 1.18-1.09 for survival of bone marrow colony-forming units. The favorable effect of incubating irradiated bone marrow with cycloheximide on the stem cell potential has been proven by experiments using a donor-recipient method. The positive effect of the reimplantation procedure and the partial extraction procedure on the stem cell potential in irradiated mice can be shown as soon as 2 h after exposure and the procedures. The results suggest that ther exist some reserves that can be stimulated to accelerate hemopoietic restoration in a heavily irradiated organism. The recruitment of these reserves seems to be related to the response of the structures producing cytokines after lethal irradiation. In addition, repair processes may be involved in the rescue of lethally irradiated hemopoietic stem cells.

Magnetic resonance imaging and histopathology in femoral head necrosis.

We correlated preoperative magnetic resonance (MR) images and histopathology of eight femoral heads from patients with osteonecrosis. The signal intensity of the MR image was low in the area where fibrovascular tissue, disintegrated fibrovascular tissue, or amorphous necrotic material occupied the medullary space. On the other hand, the necrotic marrow without revascularization showed high signal intensity. Osteonecrosis can be detected by MR imaging as soon as a certain amount of bone marrow is replaced by fibrovascular tissue.

CFU-M-derived human megakaryocytes synthesize glycoproteins IIb and IIIa

Human megakaryocytes have been shown by immunofluorescent techniques to express platelet glycoprotein IIb/IIIa antigen. We report evidence that megakaryocytes derived from human committed megakaryocytic progenitor cells in vitro (CFU-M) synthesize glycoproteins IIb and IIIa. Nonadherent light-density human bone marrow cells were cultured in human plasma and methylcellulose using conditions that promote large megakaryocytic colonies. On day 13 the megakaryocytic colonies were picked, pooled, and pulsed with 35S-methionine in methionine-free media. Populations of approximately 100,000 cells with greater than or equal to 95% viability and containing 70% to 90% megakaryocytes were obtained reliably for study. After the radioactive pulse, the cell suspension was solubilized with nonionic detergent. To reduce nonspecific binding of 35S-labeled proteins to agarose, the lysate was chromatographed sequentially on glycine-quenched Affi-gel and antihuman factor X-Sepharose. The unbound material from these resins was then chromatographed on an antiglycoprotein IIb/IIIa monoclonal antibody resin (HP1–1D-Sepharose) or on a control monoclonal antibody resin. Bound fractions were eluted and analyzed by polyacrylamide gel electrophoresis and autoradiography. Autoradiograms of diethylamine eluates from HP1–1D-Sepharose revealed two labeled proteins with electrophoretic mobilities identical with those of human platelet membrane glycoproteins IIb and IIIa, isolated using similar conditions. Autoradiograms of material synthesized by control macrophages from the same donors revealed no significant labeling of proteins in the glycoprotein IIb/IIIa molecular weight range, nor were such proteins bound by HP1–1D-Sepharose. Our observations show that protein synthesis by CFU-M-derived human megakaryocytes can be readily studied using a small amount of bone marrow aspirate as starting material. This approach will allow the study of protein synthesis by megakaryocytes from normal subjects or from subjects with clinical disorders, and it will circumvent the need to obtain large amounts of bone marrow to prepare enriched populations of megakaryocytes.

A comparison between serum ferritin concentration and the amount of bone marrow stainable iron

A comparison between serum ferritin concentration and the amount of bone marrow stainable iron

Increased pulmonary vascular permeability after bone marrow injection in sheep.

We determined the effects of injection of bone marrow into the pulmonary circulation on pulmonary fluid and protein exchange in sheep. We also assessed the roles of free fatty acid toxicity and secondary thrombosis as mediators of the changes in pulmonary fluid balance. Injection of small amounts of bone marrow (range 0.07 to 0.41 ml/kg) resulted in pulmonary edema associated with increases in steady-state pulmonary lymph flow and protein clearance that the characteristic of increased endothelial permeability. There was no change in plasma concentrations of free fatty acids after injection. The small increases in lymph fatty acid clearance paralleled the increases in lymph protein clearance, reflecting the rapid binding of fatty acids to albumin. Decreased plasma fibrinogen with a concomitant increase in fibrin degradation products followed the bone marrow injection, indicating the activation of intravascular coagulation. In addition, the leukocyte count rapidly decreased just after the bone marrow injection. These findings suggest that the increased permeability was due to intravascular coagulation and resultant fibrin entrapment and leukostasis, and was not a result of increased circulating fatty acids.