Tungsten accumulates in the intervertebral disc and vertebrae stimulating disc degeneration and upregulating markers of inflammation and pain.

Tungsten is incorporated in many industrial goods, military applications and medical devices due to its ability to impart flexibility, strength and conductance to materials. Emerging evidence has questioned the safety of tungsten exposure as studies have demonstrated it can promote tumour formation, induce pulmonary disease and alter immune function. Although tungsten is excreted from the body it can accumulate in certain organs such as the brain, colon, liver, kidneys, spleen and bones, where most of the bioaccumulation occurs. Whether prolonged tungsten exposure leads to accumulation in other tissues is unknown. The present study demonstrated that mice exposed to 15 ppm sodium tungstate for 4 weeks in their drinking water showed comparable accumulation in both the bony vertebrae and intervertebral discs (IVDs). Lumbar IVD height was significantly reduced in tungsten-exposed mice and accompanied by decreased proteoglycan content and increased fibrosis. In addition to catabolic enzymes, tungsten also increased the expression of the inflammatory cytokines IL-1ß and tumour necrosis factor (TNF)-α as well as the neurotrophic factors nerve growth factor (NGF) and brain-derived nerve factor (BDNF) in IVD cells. Tungsten significantly increased the presence of nociceptive neurons at the endplates of IVDs as observed by the expression of calcitonin gene-related peptide (CGRP) and anti-protein gene product 9.5 (PGP9.5) in endplate vessels. The present study provided evidence that tungsten may enhance disc degeneration and fibrosis as well as increase the expression of markers for pain. Therefore, tungsten toxicity may play a role in disc degeneration disease.

Systemic bevacizumab for the treatment of chronic bleeding in hereditary haemorrhagic telangiectasia.

BACKGROUND: Hereditary haemorrhagic telangiectasia (HHT) is a rare hereditary multisystem vascular disorder causing visceral arteriovenous malformations and mucocutaneous bleeding. Chronic gastrointestinal bleeding and epistaxis often produce profound anaemia refractory to conventional treatment. Bevacizumab, an anti-vascular endothelial growth factor monoclonal antibody, may be effective in treatment of bleeding in HHT. METHODS: All HHT patients treated with systemic bevacizumab for chronic bleeding were selected for retrospective analysis. Data collected included demographics, baseline HHT characteristics, epistaxis grade, surgical interventions, bevacizumab dosing, adverse events, haemoglobin, red cell transfusions, intravenous iron infusions, and other anaemia and/or bleeding-directed therapies. RESULTS: Thirteen HHT patients were treated with bevacizumab for a median of 13.9 (range 4.9-30.1) months. Compared with pretreatment values, bevacizumab treatment increased the mean haemoglobin by 4.0 g dL-1 (95% CI, 2.6-5.3 g dL-1 ) [mean (95% CI) haemoglobin 8.5 (7.8, 9.9) g dL-1 vs. 12.5 (11.2, 13.7) g dL-1 , P < 0.001)], reduced red cell units transfused by 92% [median of 6 (range 0-59) units vs. 0 (range 0-15) units, P = 0.004] and reduced quantity of iron infused by 73% [mean (95% CI) 462 (257, 668) mg month-1 vs. 126 (75, 178) mg month-1 , P = 0.002]. Epistaxis control was achieved in 85% with bevacizumab versus 0% before treatment (P < 0.001). No patient required nasal or GI procedures during the maintenance period. Two patients (15%) developed grade 3 hypertension requiring medical management. CONCLUSION: Systemic bevacizumab was highly effective to treat chronic bleeding in HHT. Further study is needed to confirm the magnitude of benefit and further define optimal dosing, treatment duration and long-term safety.

Perioperative thrombocytopenia: evidence, evaluation, and emerging therapies.

Thrombocytopenia is a common perioperative clinical problem. While global haemostasis is influenced by many patient- and procedure-related factors, the contribution of thrombocytopenia to bleeding risk is difficult to predict, as platelet count does not linearly correlate with likelihood of bleeding. Thus, the widely used definition of thrombocytopenia and grading of its severity have limited clinical utility. We present a summary and analysis of the current recommendations for invasive procedures in thrombocytopenic patients, although the platelet count at which any given procedure may safely proceed is unknown. The benefits and risks of preoperative platelet transfusions should be assessed on a patient-by-patient basis, and alternatives to platelet transfusion should be considered. In non-emergent surgeries or in postoperative thrombocytopenic patients, haematology consultation should be considered to guide diagnostics and management. We present a pragmatic approach to the evaluation of perioperative thrombocytopenia.

Localized spirals in Taylor-Couette flow.

We present a type of spiral vortex state that appears from a supercritical Hopf bifurcation below the linear instability of circular Couette flow in a Taylor-Couette system with rigid end plates. These spirals have been found experimentally as well as numerically as "pure" states but also coexist with "classical" spirals (or axially standing waves for smaller systems) which typically appear from linear instability in counterrotating Taylor-Couette flow. These spiral states have an axial distribution of the strongly localized amplitude in the vicinity of the rigid end plates that confine the system in the axial direction. Furthermore, they show significantly different oscillation frequencies compared to the critical spiral frequencies. Despite the localization of the amplitude near the ends, the states appear as global states with spirals that propagate either toward the middle from each end of the system or vice versa. In contrast to classical spirals, these states exhibit a spatial or a spatiotemporal reflection symmetry.

Low concentrations of nitric oxide increase oxygen affinity of sickle erythrocytes in vitro and in vivo.

The hallmark of sickle cell disease (SCD) is the polymerization of deoxygenated sickle hemoglobin (HbS). In SCD patients, one strategy to reduce red blood cell (RBC) sickling is to increase HbS oxygen affinity. Our objective was to determine if low concentrations of nitric oxide (NO) gas would augment the oxygen affinity of RBCs containing homozygous HbS (SS). Blood containing normal adult hemoglobin (AA) or SS RBCs was incubated in vitro in the presence of varying concentrations of NO up to 80 ppm, and oxygen dissociation curves (ODCs) were measured. In addition, blood was obtained from three AA and nine SS volunteers, before and after breathing 80 ppm NO in air for 45 min, and the ODCs were measured. Exposure of SS RBCs to 80 ppm NO in vitro for 5 min or longer decreased the partial pressure of oxygen at which hemoglobin is 50% saturated with oxygen (P50), an average of 15% (4.8+/-1.7 mmHg mean+/-SE; P < 0.001). The increase in SS RBC oxygen affinity correlated with the NO concentration. The P50 of AA RBCs was unchanged (P > 0.1) by 80 ppm NO. In SS volunteers breathing 80 ppm NO for 45 min, the P50 decreased (P < 0.001) by 4.6+/-2.0 mmHg. 60 min after NO breathing was discontinued, the RBC P50 remained decreased in five of seven volunteers in whom the ODC was measured. There was no RBC P50 change (P > 0.1) in AA volunteers breathing NO. Methemoglobin (Mhb) remained low in all subjects breathing NO (SS Mhb 1.4+/-0.5%), and there was no correlation (r = 0.02) between the reduction in P50 and the change in Mhb. Thus, low concentrations of NO augment the oxygen affinity of sickle erythrocytes in vitro and in vivo without significant Mhb production. These results suggest that low concentrations of NO gas may offer an attractive new therapeutic model for the treatment of SCD.

Transcriptional regulation of the rat platelet factor 4 gene: interaction between an enhancer/silencer domain and the GATA site.

We used various segments of the 5' upstream region of the rat platelet factor 4 (PF4) gene coupled to the human growth hormone gene and heterologous promoters to identify domains which are critical for tissue-specific expression. Transient expression experiments with rat bone marrow cells and other cell lines revealed a complex interplay between a core promoter domain from -97 to the transcriptional start site and an enhancer/silencer domain from -448 to -112. The core promoter contains a GATA site at -31 to -28 whose mutation to TATA or AATA decreases tissue specificity and moderately affects expression in megakaryocytes as well as a positively acting subdomain from -97 to -83 whose removal decreases overall transcription without affecting tissue specificity. The enhancer/silencer domain possesses three positively acting subdomains from -380 to -362, -270 to -257, and -137 to -120 as well as a negatively acting subdomain at -184 to -151 which is able to reduce overall transcription but has no effect on tissue specificity. The subdomain from -380 to -362 is most critical in restricting gene expression driven either by the PF4 promoter or by a heterologous promoter to the megakaryocytic lineage. The subdomains from -270 to -257 and -137 to -120 function together with the subdomain from -380 to -362 to somewhat increase tissue specificity. Simultaneous mutation of the GATA site and deletion of either the whole enhancer/silencer domain or the subdomain from -380 to -362 or -137 to -120 reduce transcription in megakaryocytes by 10- to 30-fold. On the basis of the above-described results, we propose that the megakaryocyte-specific enhancer/silencer domain and the GATA site are responsible for high-level expression of the PF4 gene in a lineage-specific manner.

Botrocetin agglutination of rat megakaryocytes: a rapid method for megakaryocyte isolation.

Botrocetin isolated from the venom of Bothrops jaracara has been shown by others to induce binding of von Willebrand Factor to glycoprotein Ib and thereby produce platelet agglutination in a wide range of animal species. We have found that botrocetin also facilitates the agglutination of megakaryocytes and have used this property to develop a method to isolate megakaryocytes from rat bone marrow. When botrocetin is added to a mixture of rat bone marrow, rat platelets, and rat plasma, coagglutination of megakaryocytes and platelets occurs. The agglutinated complexes, containing > 95% of the megakaryocytes, may then be separated from the remaining marrow cells by filtration. Megakaryocytes account for 39% (range 30%-48%) of the isolated cells and 83% (range 77%-88%) of the isolated cell mass. This method allows the virtually complete removal of megakaryocytes from bone marrow as well as their isolation to a high degree of purity. It should provide a useful, inexpensive, general method for the rapid isolation of megakaryocytes from multiple, small marrow samples from a wide range of species.

rmIL-6 stimulates the transcriptional activity of the rat PF4 gene.

We have examined the effect of recombinant murine interleukin-6 (rmIL-6) on megakaryocytopoiesis in a liquid rat bone marrow culture system. At concentrations of IL-6 up to 100 ng/mL, no stimulation of megakaryocyte ploidy was observed. However, transient expression studies revealed that IL-6 did have a significant effect on the transcriptional activity of the platelet factor four (PF4) gene, a platelet alpha-granule protein gene uniquely expressed in megakaryocytes. Furthermore, when the amount of PF4 message was directly measured in megakaryocytes, it was increased three-fold in response to IL-6. We also note that the PF4 promoter contains a hexamer, CTGGGA, described as the IL-6-responsive element in other genes. Our results suggest that the platelet progeny of IL-6-stimulated megakaryocytes may have altered alpha-granule constituents.

Future directions with platelet growth factors.

Since the purification of thrombopoietin 6 years ago, c-Mpl ligands such as recombinant human thrombopoietin (rhTPO) and pegylated recombinant human megakaryocyte growth and development factor (PEG-rHuMGDF) have undergone extensive clinical investigation. Both recombinant forms have been shown to reduce the thrombocytopenia associated with nonmyeloablative chemotherapy. Several areas of research have been identified for further clinical development of c-Mpl ligands. One future direction is to continue to explore the intravenous route of administration of rhTPO and PEG-rHuMGDF, as well as fusion proteins of interleukin-3-thrombopoietin and thrombopoietin peptide mimetics, which may be as potent as thrombopoietin, but may lack antigenicity. Another focus would be on the use of these molecules in treating non-chemotherapy-induced thrombocytopenia associated with myelodysplastic syndrome (MDS), idiopathic thrombocytopenic purpura (ITP), human immunodeficiency virus (HIV)-related ITP, and liver disease. Additionally, c-Mpl ligands may have a role in improving apheresis yields when administered to normal platelet donors. Considerable data demonstrate the effectiveness of PEG-rHuMGDF in raising the platelet yields in apheresis donors. In the past few years, investigation into the use of thrombopoietin for ex vivo expansion of pluripotent stem cells has been extensive. Last, thrombopoietin may serve as a radioprotectant by preventing radiation-induced apoptosis of pluripotent stem cells. In the coming years, the clinical role of rhTPO, PEG-rHuMGDF, and related molecules such as the thrombopoietin peptide mimetics will probably be established for both chemotherapeutic and nonchemotherapeutic indications.

Association of thrombocytopenia with the use of intra-aortic balloon pumps.

PURPOSE: The intra-aortic balloon pump has become an important tool in the management of patients with severe coronary artery disease. Although pump-induced thrombocytopenia was described more than 20 years ago, there has been no prospective study of this condition. PATIENTS AND METHODS: In a prospective study of consecutive adult intensive care patients admitted with acute coronary syndromes, we compared serial platelet counts in 58 patients treated with an intra-aortic balloon pump with 51 patients who were not. All patients received intravenous heparin. RESULTS: Clinical characteristics of the two groups were similar, except that unstable angina was more frequent among balloon pump patients. On each of 6 consecutive days, the mean platelet counts of patients treated with a balloon pump were significantly lower than those of non-pump patients. Platelet counts (mean +/- SD) of balloon pump patients decreased to a nadir of 63% +/- 4% of the initial count on day 4, but subsequently stabilized. There was only a slight, transient decrease in the platelet counts of non-pump patients. Overall, 47% of balloon pump patients developed thrombocytopenia (platelet count <150,000/mm3) compared with 12% of non-pump patients (P <0.01). Platelet counts dropped by at least half of initial counts in 26% of balloon pump patients compared with 4% of non-pump patients (P <0.01). Multivariate analysis demonstrated that the use of an intra-aortic balloon pump was independently associated with a substantial (> or =50%) decline in platelet count (odds ratio 7.2, 95% confidence interval 1.4 to 40, P = 0.03). Removal of the balloon pump was associated with a rapid increase in platelet count. CONCLUSIONS: The use of an intra-aortic balloon pump led to a steady and predictable decrease in platelet count, which recovered rapidly if the balloon pump was removed or slowly if the device remained in place.

The effect of unfractionated vs. low molecular weight heparin on tissue factor pathway inhibitor levels in hospital inpatients.

Although heparin is widely used as an antithrombotic agent, its multiple mechanisms of action are not fully defined. Recent work has suggested that tissue factor pathway inhibitor (TFPI) may contribute to the antithrombotic activity of heparin by inhibiting the extrinsic pathway of coagulation. We have investigated the effect of heparin on TFPI and have found that when unfractionated heparin is given by continuous intravenous infusion to hospitalized inpatients, TFPI levels increase 2.3-fold and remain high as long as heparin is continued, but return to baseline levels soon after the infusion is stopped. In contrast, therapeutic doses of the low molecular weight heparin, dalteparin, resulted in significantly less TFPI induction. Given the increasing number of studies establishing the clinical efficacy of low molecular weight heparins as antithrombotic agents, these results suggest that TFPI may not be a major contributor to the antithrombotic effect of heparin.

The end is just the beginning: megakaryocyte apoptosis and platelet release.

Under influence of hematopoietic growth factors, particularly thrombopoietin (TPO), hematopoietic stem cells in the bone marrow go through a process of commitment, proliferation, differentiation, and maturation and become mature megakaryocytes. At this critical point, terminally differentiated megakaryocytes face a new fate: ending the old life as mature megakaryocytes by induction of apoptosis and beginning a new life as platelets by fragmentation of the large megakaryocyte cytoplasm. These events are as important as megakaryocyte commitment, proliferation, differentiation, and maturation, but the molecular mechanisms regulating these events are not well established. Although TPO drives megakaryocyte proliferation and differentiation and protects hematopoietic progenitor cells from death, it does not appear to promote platelet release from terminally differentiated megakaryocytes. Although mature megakaryocyte apoptosis is temporally associated with platelet formation, premature megakaryocyte death directly causes thrombocytopenia in cancer therapy and in diseases such as mvelodysplastic syndromes and human immunodeficiency virus infection. Also, genetic studies have shown that accumulation of megakaryocytes in bone marrow is not necessarily sufficient to produce platelets. All of these findings suggest that platelet release from megakaryocytes is an important and regulated aspect of platelet production, in which megakaryocyte apoptosis may also play a role. This review summarizes recent research progress on megakaryocyte apoptosis and platelet release.

The HIT Expert Probability (HEP) Score: a novel pre-test probability model for heparin-induced thrombocytopenia based on broad expert opinion.

BACKGROUND: The diagnosis of heparin-induced thrombocytopenia (HIT) is challenging. Over-diagnosis and over-treatment are common. OBJECTIVES: To develop a pre-test clinical scoring model for HIT based on broad expert opinion that may be useful in guiding clinical decisions regarding therapy. PATIENTS/METHODS: A pre-test model, the HIT Expert Probability (HEP) Score, was constructed based on the opinions of 26 HIT experts. Fifty patients referred to a reference laboratory for HIT testing comprised the validation cohort. Two hematology trainees scored each patient using the HEP Score and a previously published clinical scoring system (4 T's). A panel of three independent experts adjudicated the 50 patients and rendered a diagnosis of HIT likely or unlikely. All subjects underwent HIT laboratory testing with a polyspecific HIT ELISA and serotonin release assay (SRA). RESULTS: The HEP Score exhibited significantly greater interobserver agreement [intraclass correlation coefficient: 0.88 (95% CI 0.80-0.93) vs. 0.71 (0.54-0.83)], correlation with the results of HIT laboratory testing and concordance with the diagnosis of the expert panel (area under receiver-operating curve: 0.91 vs. 0.74, P = 0.017) than the 4 T's. The model was 100% sensitive and 60% specific for determining the presence of HIT as defined by the expert panel and would have allowed for a 41% reduction in the number of patients receiving a direct thrombin inhibitor (DTI). CONCLUSION: The HEP Score is the first pre-test clinical scoring model for HIT based on broad expert opinion, exhibited favorable operating characteristics and may permit clinicians to confidently reduce use of alternative anticoagulants. Prospective multicenter validation is warranted.

Improving the management of hypertension in Kazakhstan: implications for improving clinical practice, patient behaviours and health outcomes.

This paper presents findings from the assessment of a strategy aimed at improving case-finding and management of hypertension patients. Study findings suggest that providers' orientation to clinical guidelines, public information on hypertension risks, promotion of yearly blood pressure screening, and universal access to an outpatient drug benefit package, improve case-finding and management. In addition, training of providers at pilot sites resulted in a substantial and significant difference in patient care and health outcomes. Provider training and tools, especially focused on effective patient counselling, made a significant contribution to increased case-finding, patient adherence to prescribed drugs, reducing salt, and increasing regular exercise. However, further refinements are required to achieve the expected adherence of patients to medication and lifestyle advice. In the pilot area, we compared two samples of patients before and after the initiation of the intervention. We found an increase in the proportion of patients with blood pressure <140/90 mmHg, and a significant decrease in the proportion of patients with blood pressure > or =160/100 mmHg. The strategy involved the joint efforts of the Research Institute of Cardiology and Internal Diseases, Karaganda Drug Information Centre, Karaganda Oblast Health Department, Kazakhstan Association of Family Physicians, Almaty Postgraduate Institute for Physicians, and USAID ZdravPlus Project in Central Asia.

The physiology of platelet production.

The production of platelets from the bone marrow megakaryocytes is a well-regulated process. Nearly 100 years ago, James Homer Wright described how platelets formed from megakaryocytes and entered the circulation. Subsequent clinical and animal studies have enumerated a number of principles of platelet physiology: the platelet count is constant in any one individual but varies greatly between individuals; an inverse relationship exists between the platelet count and platelet size; the body conserves the mass, not the number, of platelets; and megakaryocyte number, size and ploidy vary in response to changing demands for platelets. With the discovery of thrombopoietin (TPO), a number of additional physiological principles have emerged: TPO takes 24 h to rise maximally and has a maximal half-life of 45 min; TPO levels are inversely and exponentially proportional to the platelet mass; platelets bind and clear TPO from the circulation; and hepatic TPO product on is not altered by changes in the platelet mass. Using these principles, a model for the regulation of platelet production by TPO has been proposed in which the constitutive hepatic TPO produced is removed from the circulation by the platelet mass. Changes in the platelet mass or its ability to clear TPO produce changes in TPO levels resulting in an altered platelet production rate. Using this model, a number of pathological disorders of platelet production, such as essential thrombocythemia and idiopathic thrombocytopenic purpura, are analyzed.

Thrombopoietin: biology, clinical applications, role in the donor setting.

Thrombopoietin (c-Mpl ligand) is the hematopoietic growth factor that is responsible for regulating the production of platelets from bone marrow megakaryocytes. This approximately 90 kd protein has recently been isolated and is comprised of an erythropoietin domain that is approximately 50% homologous to erythropoietin and a carbohydrate domain that is highly glycosylated and appears to stabilize the protein in the circulation. Thrombopoietin is produced in the liver and blood levels are determined by the mass of circulating platelets. However, there is no platelet "sensor." Rather platelets contain high affinity thrombopoietin receptors that bind and remove thrombopoietin from the circulation and thereby directly determine circulating levels. In vitro thrombopoietin stimulates both early and late megakaryocyte precursors as well as some erythroid and multipotential progenitor cells. When administered to normal animals, it stimulates platelet production up to six-fold without affecting other lineages. However, when given to animals following chemotherapy or irradiation, it stimulates erythroid and myeloid as well as platelet recovery. Several different recombinant thrombopoietin proteins are now entering clinical trials in humans and all preliminary reports confirm a potent thrombopoietic stimulus and apparent lack of toxicity. Thrombopoietin shows great promise in preventing the thrombocytopenia associated with chemotherapy, bone marrow transplantation, and other acute or chronic thrombocytopenic disorders. In transfusion medicine, thrombopoietin may help mobilize peripheral blood progenitor cells, stimulate donors for plateletpheresis, and enhance platelet survival and function during storage, Many studies are currently underway in all these areas and should soon establish the role of thrombopoietin in clinical medicine.

In vivo effects of Mpl ligand administration and emerging clinical applications for the Mpl ligands.

The Mpl ligands are a family of closely related hematopoietic growth factors that bind to the thrombopoietin receptor, c-Mpl. In addition to the endogenous Mpl ligand, thrombopoietin, two recombinant Mpl ligands, recombinant thrombopoietin and pegylated megakaryocyte growth and development factor (PEG-MGDF) are under investigation. Endogenous thrombopoietin regulates most of the normal production of platelets but also is essential for the normal development of other lineages. When recombinant thrombopoietin or PEG-MGDF is administered to normal animals or humans, there is a dose-dependent increase in the platelet count but no effect on leukocytes or erythrocytes. When administered following chemotherapy in animal models or humans, Mpl ligands reduce the duration and sometimes the degree of thrombocytopenia. The Mpl ligands also may be effective in reducing the thrombocytopenia of patients with HIV infection, liver disease, myelodysplasia, or after plateletpheresis.

Thrombopoietins and thrombopoiesis: a clinical perspective.

Since the discovery of thrombopoietin four years ago there has been much interest in the clinical use of this growth factor and its impact on platelet transfusions. Two recombinant thrombopoietin molecules are currently under intense clinical investigation. One is a full-length, glycosylated thrombopoietin (rHuTPO) and the other is a non-glycosylated, truncated thrombopoietin coupled to polyethylene glycol (PEG-rHuMGDF). Both bind to the thrombopoietin receptor, c-mpl, and stimulate megakaryocyte growth and platelet production in vitro and in vivo. In early clinical studies these "Mpl ligands" have been effective in reducing thrombocytopenia after non-myeloablative but not after myeloablative chemotherapy. In transfusion medicine, they may serve to increase the yield of stem cell harvests, expand progenitor cells ex vivo and stimulate platelet apheresis donors. Their impact on platelet usage is still unclear but may be less than initially estimated.

The use of PEG-rhuMGDF in platelet apheresis.

Platelet transfusions are increasingly being used to treat thrombocytopenic conditions ranging from aplastic anemia to that caused by cancer chemotherapy. Although historically whole-blood transfusions were the primary source of platelets for transfusion, random donor platelet concentrates and single-donor apheresis platelets are currently the only products used. The use of these products in the United States varies widely for different medical conditions; for example, surgical patients receive random donor platelet concentrates much more commonly than single-donor apheresis products, while the opposite is true for hematology/oncology patients. The past decade has seen a great change in the type of platelet product prescribed. Whereas random donor platelet concentrates were mostly used in the past, over 60% of the platelets transfused are now obtained from donors by apheresis. A crucial variable in the ability to collect platelets by apheresis is the donor platelet count. With the recent availability of thrombopoietin, there has been considerable interest in using this hematopoietic growth factor to stimulate platelet production in donors. Preliminary studies with the administration to platelet donors of one of the thrombopoietic growth factors, PEG-rHuMGDF, have demonstrated a marked increase in the apheresis yield and no side effects. The PEG-rHuMGDF-mobilized platelets were effective upon transfusion. Whether stimulation of platelet production in donors with thrombopoietic growth factors will become a widely accepted method will depend largely on the safety of this approach for the donor as well as on a number of lesser issues which concern the recipient and blood center.