Biomedical subjects

Ted Wun

Publications and source records attributed to Ted Wun.

17 recordsLinked to original sources

PubMed2006

Venous thromboembolism in patients with colorectal cancer: incidence and effect on survival.

PURPOSE: To describe the incidence and outcomes associated with venous thromboembolism (VTE) among patients with colorectal cancer. METHODS: This was a retrospective analysis of all colorectal cancer patients diagnosed in California between 1993 and 1995 and 1997 to 1999. Principal outcomes were incident symptomatic VTE events and death. Associations between specific risk factors and principal outcomes were analyzed using Cox proportional hazards models. RESULTS: Among 68,142 colorectal cancer patients, 50% were women, mean age was 70 +/- 15 years, and approximately 70% underwent a major operation. The 2-year cumulative incidence of VTE was 2,100 patients (3.1%), with an incidence rate that decreased significantly over time from 5.0% (events/100 patient-years) in months 0 to 6 to 1.4% during months 7 to 12 to 0.6% during the second year. Significant predictors of VTE included metastatic stage (hazard ratio [HR] = 3.2; 95% CI, 2.8 to 3.8) and three or more comorbid conditions (HR = 2.0; 95% CI, 1.7 to 2.3). The risk of VTE was significantly reduced among Asians/Pacific Islanders (HR = 0.4; 95% CI, 0.3 to 0.5.) and patients who underwent an abdominal operation (HR = 0.4; 95% CI, 0.3 to 0.4). In risk-adjusted models, VTE was a significant predictor of death within 1 year of cancer diagnosis among patients with local- (HR = 1.8; 95% CI, 1.4 to 2.3) or regional-stage disease (HR = 1.5; 95% CI, 1.3 to 1.8) but not among patients with metastatic disease (HR = 1.1; 95% CI, 1.0 to 1.2). CONCLUSION: The incidence of VTE among colorectal cancer patients was highest in the first 6 months after diagnosis and decreased rapidly thereafter. Metastatic disease and the number of medical comorbidities were the strongest predictors of VTE. Incident VTE reduced survival among patients with local or regional disease, suggesting that, in these patients, VTE may reflect the presence of a biologically more aggressive cancer.

Aged↗

PubMed2006

Low-dose warfarin does not decrease the rate of thrombosis in patients with cervix and vulvo-vaginal cancer treated with chemotherapy, radiation, and erythropoeitin.

OBJECTIVES: We had previously reported an association between the use of recombinant human erythropoietin (rHuEPO) and thrombosis in patients with cervix and vulvo-vaginal cancer treated with chemotherapy and radiation. We hypothesized that low-dose warfarin would be effective prevention for thromboembolic events in this setting. METHODS: A retrospective analysis of patients with cervical or vulvo-vaginal carcinoma receiving chemoradiation and rHuEpo was performed. Thirty-two patients received rHuEpo alone, and 24 received warfarin (1-2 mg) and rHuEpo. The primary endpoint was objectively proven symptomatic venous thrombosis. RESULTS: There was no difference in the baseline characteristics (e.g. age, stage, body mass index, mean and peak hemoglobin, WBC and platelet counts, and number of transfusions) between these two groups. The rate of thrombosis also was not statistically different (P = 0.62). Nine of 24 patients had a symptomatic deep vein thrombosis (DVT) while receiving warfarin compared to 10 of 32 patients not on warfarin. There was no difference between the two groups in the percentage of patients with upper extremity DVT (P = 0.83) or lower extremity DVT (P = 0.64). CONCLUSION: Daily low-dose warfarin did not alter the incidence of symptomatic DVT in patients with cervical or vulvo-vaginal cancer who received rHuEpo in conjunction with chemoradiation.

Anticoagulants↗

PubMed2006

Lipoprotein(a) and thrombocytes: potential mechanisms underlying cardiovascular risk.

Plasma levels of lipoprotein(a), Lp(a), is an independent risk factor for cardiovascular disease. Lp(a) has many properties in common with low-density lipoprotein (LDL), including a cholesteryl ester-rich lipid core and the presence of one copy of apolipoprotein B-100; both apoB-100 and the lipid core are pro-atherogenic. In addition, Lp(a) contains a unique hydrophilic, carbohydrate-rich protein, apo(a), linked to apoB through a single disulfide bond connecting the C-terminal regions of the two proteins. The similarities between apolipoprotein(a), apo(a), and plasminogen has initiated numerous studies on the possible role of Lp(a) as a prothrombotic agent. Studies to date suggest that Lp(a) has antifibrinolytic and procoagulant properties. In this review, we summarize recent studies focused on the interaction between Lp(a) and platelets. Collectively, results to date illustrate that thrombogenicity associated with Lp(a) could be due to risk associated with the LDL moiety, with the apo(a) moiety, or from the combination of those in Lp(a). Present findings suggest that the various components of Lp(a) may impact to a varying degree on different underlying pathways involved in platelet activation and aggregation. On balance, results indicate an effect by Lp(a) on platelet function and future studies focused on specific Lp(a) components, such as the role of apo(a) and of the LDL-like lipid moiety, are needed.

Apolipoproteins A↗

PubMed2005

Evaluation of factors affecting awareness of and willingness to participate in cancer clinical trials.

PURPOSE: Annually, only 3% of patients participate in cancer clinical trials (CCTs). Barriers to accrual include lack of CCT awareness and uncertain third-party payer coverage. In January 2002, a California law (Senate Bill 37 [SB37]) required all third-party payers to reimburse patient care costs related to CCTs. We evaluated the level of awareness of patients and/or their family members/friends regarding CCTs and SB37. METHODS: We used both a written survey for patients and/or their family members and friends seen in oncology clinics, and a verbal telephone version for Cancer Information Service callers. We tested for correlations between CCT awareness and SB37 knowledge, and willingness to participate in CCTs. RESULTS: Of 1,188 respondents, 59% were aware of CCTs, 19% knew of SB37, and 36% were very likely to consider a CCT. There were significant positive correlations between CCT awareness and willingness to participate (P < .001, Spearman), and between SB37 knowledge and willingness to participate (P = .001, Pearson chi2). Reduced awareness was seen in respondents who were either black or African American (odds ratio [OR], 0.44; P = .004), Hispanic (OR, 0.56; P = .03), had an annual income less than 25,000 dollars (OR, 0.38; P < .001), or had less than a college degree (OR, 0.12 to 0.53; P < .001 to .013). Reduced willingness to participate in CCTs was seen in black or African American participants (OR, 0.38; P < .001), Asians (OR, 0.44; P < .006), or respondents aged 18 to 24 years (OR, 0.35; P = .002). CONCLUSION: These results support the hypothesis that improving CCT awareness and SB37 knowledge especially among lower income, less educated, and minority patients, may potentially overcome barriers to participation and subsequently increase accrual in California.

Adolescent↗

PubMed2005

High-dose radioimmunotherapy combined with fixed, low-dose paclitaxel in metastatic prostate and breast cancer by using a MUC-1 monoclonal antibody, m170, linked to indium-111/yttrium-90 via a cathepsin cleavable linker with cyclosporine to prevent human anti-mouse antibody.

PURPOSE: Although radioimmunotherapy alone is effective in lymphoma, its application to solid tumors will likely require a combined modality approach. In these phase I studies, paclitaxel was combined with radioimmunotherapy in patients with metastatic hormone-refractory prostate cancer or advanced breast cancer. EXPERIMENTAL DESIGN: Patients were imaged with indium-111 (111In)-1,4,7,10-tetraazacyclododecane-N,N',N'',N'''-tetraacetic acid-peptide-m170. One week later, yttrium-90 (90Y)-m170 was infused (12 mCi/m2 for prostate cancer and 22 mCi/m2 for breast cancer). Initial cohorts received radioimmunotherapy alone. Subsequent cohorts received radioimmunotherapy followed 48 hours later by paclitaxel (75 mg/m2). Cyclosporine was given to prevent development of human anti-mouse antibody. RESULTS: Bone and soft tissue metastases were targeted by 111In-m170 in 15 of the 16 patients imaged. Three prostate cancer patients treated with radioimmunotherapy alone had no grade 3 or 4 toxicity. With radioimmunotherapy and paclitaxel, two of three prostate cancer patients developed transient grade 4 neutropenia. Four breast cancer patients treated with radioimmunotherapy alone had grade 3 or 4 myelosuppression. With radioimmunotherapy and paclitaxel, both breast cancer patients developed grade 4 neutropenia. Three breast cancer patients required infusion of previously harvested peripheral blood stem cells because of neutropenic fever or bleeding. One patient in this trial developed human anti-mouse antibody in contrast to 12 of 17 patients in a prior trial using m170-radioimmunotherapy without cyclosporine. CONCLUSIONS: 111In/90Y-m170 targets prostate and breast cancer and can be combined with paclitaxel with toxicity limited to marrow suppression at the dose levels above. The maximum tolerated dose of radioimmunotherapy and fixed-dose paclitaxel with peripheral blood stem cell support has not been reached. Cyclosporine is effective in preventing human anti-mouse antibody, suggesting the feasibility of multidose, "fractionated" therapy that could enhance clinical response.

Adult↗

PubMed2005

Safety and efficacy of rituximab in patients with rheumatoid arthritis refractory to disease modifying antirheumatic drugs and anti-tumor necrosis factor-alpha treatment.

OBJECTIVE: To determine the safety and efficacy of rituximab treatment in patients with active seropositive rheumatoid arthritis (RA) who had experienced an inadequate response to treatment with anti-tumor necrosis factor-alpha agents and/or traditional disease modifying antirheumatic drugs. METHODS: Rituximab was administered to 17 patients as weekly infusions for 4 consecutive weeks. Patients continued their baseline therapy and were followed for 28 weeks. RESULTS: All patients were evaluable for safety, and 13 for efficacy. Profound B cell depletion occurred by 12 weeks and was sustained at 24 weeks, whereas T cell, complement, and immunoglobulin levels remained within normal ranges. Rituximab was well tolerated, with no infusion related reactions and only mild/moderate adverse events. American College of Rheumatology 20% response (ACR20) was achieved in 55% of patients by Week 5, 75% by Week 8, 50% at Week 16, and 67% at Week 28. Corresponding ACR50 and ACR70 responses were achieved in 36% and 18%, 25% and 17%, 42% and 25%, and 33% and 17% of patients at Weeks 5, 8, 16, and 28, respectively. There were significant improvements over baseline in tender and swollen joint counts (p < 0.0001), physician's global assessment of disease activity (p = 0.0001), and patient assessed pain (p = 0.0005) and disability (p = 0.0386). Erythrocyte sedimentation rate (p = 0.0361) and rheumatoid factor titers (p < 0.0001) also decreased significantly. CONCLUSION: These results support the hypothesis that B cells play an important role in RA pathophysiology, and suggest that rituximab is effective and well tolerated, with a rapid onset of clinical benefit, in patients with refractory, seropositive active RA.

Aged↗

PubMed2004

Acute myocardial infarction in hemoglobin SC disease.

Although there are reports of myocardial infarction (MI) in patients with sickle cell diseases, an antemortem diagnosis of acute MI in a patient with compound heterozygous hemoglobin SC disease has not been reported. Herein, we present a patient with hemoglobin SC who suffered an acute MI. She had typical chest pain for myocardial ischemia, associated with ST elevations on the electrocardiogram (EKG) and elevations of cardiac injury markers diagnostic of infarction. The patient was treated with conventional therapies for acute coronary syndrome and also emergent red blood cell exchange. Interestingly, coronary angiography was completely normal in this patient. Potential mechanisms and management for acute MI in patients with sickle cell disease are discussed.

Adult↗

PubMed2004

Inflammatory potential of neutrophils detected in sickle cell disease.

An early event in the inflammatory response is neutrophil recruitment to endothelium in response to chemotactic stimulation, which in turn activates CD18-integrin, which anchors neutrophils to the vessel wall under the shear force of blood flow. Activated neutrophils circulating in sickle cell disease (SCD) patients may significantly contribute to vascular occlusions (VOC) as neutrophils adherent to inflamed endothelium recruit sickle red blood cells inducing VOC. To elucidate the mechanisms by which neutrophils may participate in VOC in SCD, CD18-integrin expression and function in fresh blood samples of non-crisis patients were measured by flow cytometry. CD11b/CD18 membrane expression was approximately 70% higher on unstimulated SCD neutrophils than controls, which correlated with a 1-fold higher rate of adhesion to ligand. Unstimulated SCD neutrophils expressed approximately 30,000 active CD18 per cell, while controls expressed approximately 6,000. Stimulation with a low concentration of IL-8 (0.1 nM) upregulated 100% more active CD18 and induced 60% more adhesion of SCD than control neutrophils. These data demonstrate that neutrophils from SCD patients constitutively express active CD18 in blood and respond with enhanced sensitivity to chemokine activation of adhesion, thus increasing their propensity for exuberant adhesion.

Adult↗

PubMed2004

Increased cyclooxygenase-2 (COX-2): a potential role in the pathogenesis of lymphoma.

B cell lymphomas are a diverse group of clinicopathologic diseases with an increasing incidence. As with other malignancies, the accumulation of genetic abnormalities are required for malignant transformation of human lymphocytes. Cyclooxygenase-2 (COX-2) is a key biosynthetic enzyme in prostaglandin synthesis and has been implicated in the pathogenesis of numerous malignancies including colon, breast, and lung cancer. There is little data on the potential role of COX-2 in lymphoma pathogenesis. In this study, several B lymphoma cell lines and primary B cells obtained from normal volunteer controls were examined for COX-2 protein expression. Immunoblot analysis demonstrated between an approximately 2.2-4.3-fold increase in COX-2 protein expression relative to primary B cells in all lymphoma cell lines examined. Increased COX-2 phosphorylation was found in the BJAB, BL41, and Raji cells whereas the levels in Daudi, Namalwa, and Ramos did not differ from that of primary B cells. Treatment with 25-100 microM celecoxib (CEL) resulted in decreased proliferation as measured by [3H]thymidine in all cell lines examined, and the effect was dose-dependent, and not significantly enhanced by chlorambucil (CHL). The effect of COX-2 inhibition on apoptosis in lymphoma cells was examined and revealed apoptotic induction of greater than 85% in all cell lines examined at 50 microM celecoxib. The pro-apoptotic effect was dose-dependent, and was not significantly enhanced by chlorambucil. Examination of apoptosis-related proteins by immunoblot analysis revealed levels of BCL-2, BCL-X(L), and Bax to be unaffected by celecoxib. In contrast, levels of Akt, MCL-1, and phosphorylated SAP-kinase were all decreased after incubation with 50 microM celecoxib. These findings suggest that increased COX-2 expression and activity, contributes to the pathogenesis of B cell lymphomas and point to a possible role for COX-2 inhibition in their treatment.

Apoptosis↗

PubMed2004

Effects of poloxamer 188 treatment on sickle cell vaso-occlusive crisis: computer-assisted intravital microscopy study.

Nine patients with sickle cell disease (SCD) who were hospitalized at UC Davis Medical Center for vaso-occlusive crisis (VOC) were studied as part of a randomized double-blind phase III clinical trial to investigate the real-time effects of poloxamer 188 on VOC. All patients showed significant microvascular changes from normal (steady-state) values during VOC (diminished venular diameter and red cell velocity). The patients were randomly assigned to be treated with poloxamer 188 or placebo. Poloxamer 188 (n = 4) but not placebo (n = 5) significantly reversed these microvascular changes approximately 2 hours postinitiation of loading infusion (100 mg/kg in 1 hour). Further significant improvement induced by poloxamer 188 but not placebo was observed > or = 7 hours postinfusion, resulting in a significant reversal of the microvascular changes to steady-state values.

Adolescent↗

PubMed2003

SU5416 plus interferon alpha in advanced renal cell carcinoma: a phase II California Cancer Consortium Study with biological and imaging correlates of angiogenesis inhibition.

PURPOSE: Vascular endothelial growth factor (VEGF) is expressed in up to 70% of renal cell carcinomas (RCCs) and is a rational therapeutic target. SU5416 is a small molecule inhibitor of VEGF-mediated signaling through Flk-1, a transmembrane tyrosine kinase. IFN-alpha also possesses dose- and schedule-dependent antiangiogenic effects at doses lower than those used for RCC therapy. We hypothesized that SU5416 plus low dose IFN-alpha 2B (Intron-A) would result in a 1-year event-free survival (EFS), exceeding 20% in patients with metastatic RCC using the results of a randomized immunotherapy trial as historical control. Efficacy was correlated with serial plasma VEGF and plasminogen activator inhibitor-1 levels and with positron emission tomography scans. EXPERIMENTAL DESIGN: Thirty patients were treated with SU5416 145 mg/m(2) i.v. twice weekly plus Intron-A 1 million units s.c. twice daily, cycled every 6 weeks. RESULTS: Fifteen patients (50%) had stable disease (SD) at 12 weeks, including 1 minor response and 8 with progressive disease (27%). Median survival time was 10 months, and 1-year EFS was 6% (95% confidence interval, 1-35). The most common grade 3 or 4 toxicities included fatigue and lymphopenia, among others. There were 3 on-study deaths, 2 of which were infection-related. Significant declines in median plasma levels of VEGF pre- and posttherapy were observed. In 5 patients with paired FDG and O-15 positron emission tomography scans, tumor metabolism and perfusion were unchanged in 3 patients with SD, increased in 1 patient with progression, and decreased in 1 patient with SD. CONCLUSIONS: Although SU5146 plus low-dose IFN exhibits biological activity in RCC as evidenced by significant declines in serial VEGF and plasminogen activator inhibitor-1 plasma levels, the 1-year EFS of 6% and adverse toxicity profile diminishes enthusiasm for additional studies with this combination in advanced RCC.

Adult↗

PubMed2003

Increased incidence of symptomatic venous thrombosis in patients with cervical carcinoma treated with concurrent chemotherapy, radiation, and erythropoietin.

BACKGROUND: Because studies have suggested that anemia has an adverse effect on outcome for patients with cervical carcinoma who are treated with radiation, recombinant human erythropoietin (rHuEpo) has been used increasingly to maintain hemoglobin levels in these patients. Erythropoietin may increase the risk of thrombosis. The authors performed a retrospective analysis to determine whether there was an increased rate of symptomatic venous thrombosis associated with the use of rHuEpo in patients with carcinoma of the uterine cervix and vagina. METHODS: A retrospective, case-control study was performed on consecutive patients with localized carcinoma of the uterine cervix or vagina who were treated with chemotherapy and radiation (chemoradiotherapy). The primary outcome was symptomatic venous thrombosis. RESULTS: One hundred forty-seven patients were reviewed. When they were divided into women who received rHuEpo (n = 75 patients) and women who did not receive rHuEpo (n = 72 patients), there were no significant differences in age, height, weight, disease stage, or body mass index. Fewer patients in the rHuEpo group required transfusions. In the rHuEpo group, 17 of 75 patients had either an upper extremity thrombosis (n = 12 patients) or a lower extremity thrombosis (n = 7 patients): 2 patients had both, and 2 patients had more than 1 event. Two of 72 patients who did not receive rHuEpo had symptomatic thrombosis. Patients who received rHuEpo had an odds ratio (OR) of developing thrombosis of 10.3 (95% confidence interval [95% CI], 2.3-46.2). Multiple logistic regression revealed that only the use of rHuEpo was associated with an increased risk of thrombosis (OR, 15.3; 95% CI, 3.1-76.7). CONCLUSIONS: Patients with cervical carcinoma who received chemoradiotherapy and rHuEpo had an increased risk of symptomatic venous thrombosis.

Adult↗

PubMed2002

Microvascular abnormalities in sickle cell disease: a computer-assisted intravital microscopy study.

The conjunctival microcirculation of 18 homozygous sickle cell disease (SCD) patients during steady-state, painful crisis, and postcrisis conditions was recorded on high-resolution videotapes using intravital microscopy. Selected videotape sequences were subsequently coded, frame-captured, studied, and blindly analyzed using computer-assisted image analysis protocols. At steady-state (baseline), all SCD patients exhibited some of the following morphometric abnormalities: abnormal vessel diameter, comma signs, blood sludging, boxcar blood flow phenomenon, distended vessels, damaged vessels, hemosiderin deposits, vessel tortuosity, and microaneurysms. There was a decrease in vascularity (diminished presence of conjunctival vessels) in SCD patients compared with non-SCD controls, giving the bulbar conjunctiva a "blanched" avascular appearance in most but not all SCD patients during steady-state. Averaged steady-state red cell velocity in SCD patients was slower than in non-SCD controls. During painful crisis, a further decrease in vascularity (caused by flow stoppage in small vessels) and a 36.7% +/- 5.2% decrease in large vessel (mostly venular) diameter resulted. In addition, the conjunctival red cell velocities either slowed significantly (6.6% +/- 13.1%; P <.01) or were reduced to a trickle (unmeasurable) during crisis. The microvascular changes observed during crisis were transient and reverted to steady-state baseline after resolution of crisis. When combined, intravital microscopy and computer-assisted image analysis (computer-assisted intravital microscopy) represent the availability of a noninvasive tool to quantify microvascular abnormalities in vascular diseases, including sickle cell disease. The ability to identify and relocate the same conjunctival vessels for longitudinal studies uniquely underscores the applicability of this quantitative real-time technology.

Adolescent↗

PubMed2002

The effects of flavanol-rich cocoa and aspirin on ex vivo platelet function.

BACKGROUND: Flavanols modulate platelet function in vitro, but less is known of their in vivo effects and how they compare to pharmacological platelet inhibitors. We investigated the effect of a flavanol-rich cocoa beverage (897 mg/ml) in combination with and in comparison to aspirin on platelet function and activation in healthy subjects. METHODS AND RESULTS: On separate test days in a crossover design, 16 healthy adults consumed aspirin (81 mg), cocoa (as a beverage), or aspirin plus cocoa. Platelet activation was measured by surface expression of P-selectin and PAC-1 binding to the activated conformation of the GPIIb/IIIa receptor (GPIIb/IIIa-act). Platelet function was measured on an analyzer (the PFA-100) that measures shear stress-induced platelet plug formation in response to collagen-epinephrine or collagen-ADP. Plasma epicatechin concentrations peaked approximately 2 h after subjects were given either the cocoa or aspirin plus cocoa. After 6 h, cocoa inhibited epinephrine-induced platelet function. Epinephrine-induced platelet function was inhibited 2 and 6 h after aspirin, and after aspirin plus cocoa. Epinephrine-stimulated P-selectin expression was inhibited by aspirin at 6 h, and after 2 and 6 h by aspirin plus cocoa. ADP-stimulated P-selectin expression was not affected by the treatments. Cocoa and aspirin, given separately, reduced epinephrine-stimulated GPIIb/IIIa-act expression at 2 and 6 h, respectively, and at 2 and 6 h when given together, suggesting an additive effective. ASA plus cocoa inhibited ADP-stimulated GPIIb/IIIa-act expression at 6 h. CONCLUSIONS: Flavanol-rich cocoa inhibited epinephrine-stimulated platelet activation and function. These effects were qualitatively similar to aspirin, but less profound. These results emphasize the need to further examine the effects of food flavonoids for platelet modulating effects.

Adult↗

PubMed2002

Acetaminophen and diphenhydramine as premedication for platelet transfusions: a prospective randomized double-blind placebo-controlled trial.

Non-hemolytic transfusion reactions (NHTR) occur in up to 30% of patients receiving platelet transfusions. Premedication with acetaminophen and diphenhydramine is a common strategy to prevent NHTR, but its efficacy has not been studied. In this prospective trial, transfusions in patients receiving pre-storage leukocyte-reduced single-donor apheresis platelets (SDP) were randomized to premedication with either acetaminophen 650 mg PO and diphenhydramine 25 mg IV, or placebo. Fifty-one patients received 98 transfusions. Thirteen patients had 15 NHTR: 15.4% (8/52) in the treatment arm and 15.2% (7/46) in the placebo arm. Premedication prior to transfusion of pre-storage leukocyte reduced SDP does not significantly lower the incidence of NHTR as compared to placebo.

Acetaminophen↗

PubMed2002

Activated monocytes and platelet-monocyte aggregates in patients with sickle cell disease.

Tumour necrosis factor-alpha (TNF-alpha) and interleukin-1beta (IL-1beta) increase endothelial surface receptors that mediate the adherence of sickle erythrocytes to the endothelium. Increased circulating levels of these cytokines have been found in patients with sickle cell disease (SCD). Monocytes are a source of both of these inflammatory mediators; we therefore determined whether circulating monocytes were activated in SCD, as defined by intracellular expression of these cytokines. Blood was also assayed for the presence of platelet-monocyte aggregates (PMAs), as platelet adherence is one possible mechanism for monocyte activation. The median percentages of monocytes expressing intracellular TNF-alpha and IL-1beta in SCD patients were 6.8 (2.8-17.3) [median (range)] and 14.1 (1.3-44.8), respectively. In African-American controls the corresponding percentages were 0.3 (0.1-0.5) and 0.4 (0.1-3.0), and in Caucasians 0.2 (0.1-0.5) and 0.8 (0.8-1.9) (P < 0.001, Kruskal-Wallis). The mean percentage (+/- SD) of PMA was 14.0 +/- 8.3 for Caucasian controls, 25.7 +/- 7.3 for African-American controls, and 45.7 +/- 21.6 for patients with SCD (P < 0.001, RM ANOVA; P < 0.05, Newman-Keuls posthoc test). We conclude that there are increased circulating PMAs and monocyte activation in patients with SCD.

Adolescent↗

PubMed2001

The Role of Inflammation and Leukocytes in the Pathogenesis of Sickle Cell Disease; Haemoglobinopathy.

Acute and chronic vascular occlusion underlies much of the morbidity and mortality in sickle disease. Abnormal polymerization of deoxygenated hemoglobin S (HbS) resulting in stiff, non-deformable erythrocytes is central to sickle cell pathogenesis. However, a complex interplay of many factors determines the balance between adequate blood flow and vessel obstruction. Serum markers of inflammation have provided evidence for a state of chronic inflammation in sickle cell disease (SCD). Inflammation promotes endothelial adherence to sickle erythrocytes. Studies demonstrating a beneficial effect of steroid therapy for painful episodes and acute chest syndrome provide indirect evidence for the role of inflammation in this disease. Leukocytosis, in the absence of infection, is common in SCD patients and predicts for stroke, acute chest syndrome, and overall mortality. Neutrophils and monocytes have been shown to be activated in these patients. Activated leukocytes further promote vascular inflammation and vessel damage. A reduction in leukocytes, and thus inflammation, may partially explain the beneficial effects of hydroxyurea in this disease. These data provide a strong rationale for clinical studies of therapy directed at inflammation and/or leukocytes in sickle cell disease.

Journal Article↗