Comparison of bone marrow extracellular matrices.

We have compared the structure and composition of adult and fetal bovine bone marrow extracellular matrices. In contrast to fetal bone marrow, adult bone marrow has more oval fenestration and accumulation of adipocytes as well as lower protein content. These differences could be due to remodeling of bone marrow tissue as it develops. Zymogram analysis of matrix metalloproteinase (MMP) and tissue inhibitor of MMP (TIMP) activities showed that fetal, but not adult bone marrow extract contained a 96-kDa MMP and TIMP-1 and -2. These activities may contribute to the structural differences between adult and fetal bone marrow tissues.     

Registry of unrelated bone marrow donors.

Reports of successful transplantation of bone marrow obtained from unrelated donors who were histocompatibility leukocyte antigen (HLA) identical prompted the Canadian Red Cross Blood Transfusion Service in Ottawa to assess the possibility of developing a bone marrow donor registry in Canada. We sent a pamphlet that explained the program to 1568 people who had undergone apheresis and asked them to reply, stating their interest. At the same time the pamphlets and a poster were placed in the blood donor clinic. We received 1232 replies (78.6%) from the apheresis donors, 838 (68.0%) of which indicated a willingness to attend information sessions. Of the 7158 people who gave blood during the 3-month study period, 225 (3.1%) were interested. At the time this paper was written 47 information sessions had been held, and 721 people had attended, 624 (86.5%) of whom had signed a consent form. This indicates a clear interest in a bone marrow donation program. We believe that the ethical issues are overcome by requesting the donation before identification of any patient. From our experience a national registry of unrelated donors seems feasible, and steps are being taken to implement such a program.     

Kinetic-microarchitectural correlations in the bone marrow of the mouse.

Transverse histologic sections of bone marrow obtained from mice that were sacrificed by perfusion fixation at intervals following tritiated thymidine injection were studied by means of radioautography. A kinetic gradient was demonstrated across the marrow section, with the highest proliferative rate in the subendosteal region. Megakaryocytes were shown to originate from the rapidly proliferating subendosteal cells. The immediate proliferating precursors of mature granulocytes were slowly proliferating cells found predominantly in the central region of the marrow. It was concluded that in the steady state there must be a migration of cells from the subendosteal region to the central region with concomitant growth retardation of the migrating cells.     

The immunoregulatory role of bone marrow. IV. Role of an immunoenhancing glycoprotein derived from murine bone marrow

Bone marrow-enhancing factor (B-EF) is the spontaneous product of whole bone marrow cells cultured in serum-free medium for a short term (24-48 hr). The factor is prepared by ultrafiltration of BMC supernates to yield a preparation with a MW of greater than 10,000. Production of the factor is not dependent upon antigenic or mitogenic stimulation of BMC, but is inhibited by treatment of BMC with cycloheximide. B-EF augments the in vitro primary PFC response to SRBC, as well as in vitro secondary IgM and IgG PFC responses to SRBC. Enhancement by B-EF is antigen dependent, genetically nonrestricted, and maximal when present at the initiation of culture. B-EF cannot induce a polyclonal antibody response like the polyclonal activator LPS. B-EF is directly mitogenic for thymocytes, bone marrow, and whole spleen cells, but fails to act as a costimulator of thymocyte proliferation in the presence of Con A. B-EF cannot support the growth of the IL-2-dependent cell line CTLL-2. Since B-EF has not been purified, the supernatant may contain more than one activity. The factor is heat labile at 65 degrees C and is sensitive to enzymatic digestion with trypsin and neuraminidase; this implies that B-EF may be a glycoprotein.     

Elimination of T lymphocytes from the bone marrow in HLA-incompatible bone marrow transplantation

The method presented is very well suited to eliminate T-lymphocytes from great amounts of bone-marrow. The stem cells required to reconstitute the bone-marrow are enriched in this way. It can be completely performed in a closed system. Any contamination with germs is excluded. It can be reproduced well and learnt quickly. It takes 10 hours for two trained co-workers to process 1,500 ml of bone-marrow. The vitality of cells is very good (100%). Its suitability for transplantation has still to be checked.     

Antibody formation in mouse bone marrow. IX. Peripheral lymphoid organs are involved in the initiation of bone marrow antibody formation.

Mouse bone marrow is barely capable of plaque-forming cell (PFC) activity during the primary response to sheep red blood cells (SRBC). However, during secondary-type responses, it becomes the major organ, containing IgM, IgG, and IgA PFC. In the present paper, the influence of splenectomy (Sx) upon the secondary bone marrow PFC response to SRBC was investigated. When previously primed mice were splenectomized just before the second intravenous (iv) injection of SRBC, the effect of Sx upon the height of the bone marrow PFC response was dependent on the booster dose. Sx just before a booster of 10⁶ SRBC iv almost completely prevented bone marrow PFC activity, whereas an iv booster dose of 4 × 10⁸ SRBC evoked a normal IgM, IgG, and IgA PFC response in Sx mice. Apparently low doses of iv administered antigen require the spleen in order to evoke antibody formation in the bone marrow. Experiments with parabiotic mice, consisting of Sx and sham-Sx mice, showed that this facilitating influence of the spleen upon bone marrow antibody formation occurs via the blood stream. In a subsequent study, it was investigated whether the spleen is required throughout the bone marrow PFC response or only during the few days of the initiation phase. Therefore, mice were splenectomized at different intervals after a booster injection of 10⁶ SRBC iv. It appeared that Sx 2 days after the booster injection could still prevent the normal bone marrow PFC activity, whereas Sx at Day 4 could no longer do so. Apparently, after an iv booster injection, the spleen is only required for initiation of the bone marrow PFC response and not for the maintenance of this PFC activity thereafter.     

The diagnostic value of bone marrow iron.

The light and electronmicroscopic representation of non-haemiron in the bone-marrow provides the unique opportunity of extensively evaluating the iron metabolism. In the bone-marrow, macrophages represent the physiological place of iron storage. The iron in the cytoplasma is stored in them in the form of free ferritin molecules and lysomally as aggregated ferritin and/or haemosiderin in siderosomes. In an equal iron balance and unimpaired internal iron exchange only erythroblasts (sideroblasts) and erythrocytes (siderocytes) of the bone-marrow besides macrophages possess siderosomes. In addition to this physiological or orthotopic iron storage a heterotopic iron storage can be observed under pathological conditions, particularly with iron overloading of the organism, in the endothelial cells of sinusoids and plasma cells. In detail, the patterns of iron storage in the bone-marrow are described in the different stages of iron deficiency, disturbance of iron utilization in chronically inflammatory processes or tumour diseases, condition after intravenous iron administration, transfusion siderosis, hereditary haemochromatosis and sideroblastic anaemia.