Safety and efficacy of adoptive cell transfer using autologous tumor infiltrating lymphocytes (LN-145) for treatment of recurrent, metastatic, or persistent cervical carcinoma

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Background: There is a high unmet medical need for effective treatments for patients with recurrent, metastatic, or persistent cervical cancer. Most patients are young and survival rates are poor. ORR for second line therapies is between 4 and 14% for chemotherapy and recently approved immunotherapy. Adoptive cell transfer using tumor infiltrating lymphocytes (TIL) have demonstrated durable responses in some patients with recurrent cervical cancer thus offering the potential for long-term disease control. Methods: Study C-145-04 is an ongoing, open-label, multicenter Phase 2 clinical trial evaluating the safety and efficacy of LN-145 TIL therapy in patients with advanced cervical cancer who have undergone at least one prior line of chemotherapy. Prior checkpoint inhibitor therapy is an exclusion criterion. The primary endpoint is ORR per RECIST 1.1; secondary endpoints include duration of response (DOR), disease control rate (DCR), and LN-145 safety. Tumors surgically harvested at local institutions are shipped to central GMP facilities for TIL generation in a 22-day manufacturing process. Final LN-145 TIL product is cryopreserved and shipped to sites. Patients receive one week of preconditioning lymphodepletion (cyclophosphamide, fludarabine), a single LN-145 infusion, followed by up to 6 doses of IL-2 (600,000 IU/kg). Results: As of 4 Feb 2019, 27 efficacy-c patients have received Gen 2 of LN-145, with a mean age of 47 years and 2.6 mean prior lines of therapy. Preliminary efficacy results: ORR was 44% (1 CR, 9 PR, 2 uPR), DCR was 89% at 3.5-month median study follow-up with 11/12 patients maintaining their response. Improved responses were observed in 4 patients with longer follow-up. Mean TIL cells infused was 28x109. Median IL-2 doses administered was 6.0. The adverse event profile was generally consistent with the underlying advanced disease and the profile of the lymphodepletion and IL-2 regimens. Conclusions: LN-145 results in 44% ORR in previously treated cervical cancer patients with acceptable safety and efficacy profile. LN-145 offers patients a viable therapeutic option warranting further investigation. Clinical trial information: NCT03108495.

Nitric oxide and cyclic GMP levels in sickle cell patients receiving hydroxyurea

Recent studies suggest that nitric oxide (NO) may partly be responsible for the beneficial effect of hydroxyurea (HU) in sickle cell disease (SCD) patients. NO stimulates cyclic guanosine monophosphate (cGMP) production, which mediates vasodilatation. We investigated the association between NO, cGMP and fetal haemoglobin (HbF) levels after HU administration. Our data showed that chronic HU significantly increased NO, cGMP, and HbF levels in SCD. Recently it was shown that HbF production was stimulated by cGMP-dependent protein kinase. Our results suggest that NO stimulates cGMP production, which then activates a protein kinase and increases the production of HbF.

Nitric Oxide Metabolites in Sickle Cell Anemia Patients after Oral Administration of Hydroxyurea; Hemoglobinopathy

The mechanism of action of hydroxyurea (HU) in decreasing the frequency of pain crisis in sickle cell disease (SCD) has not been fully elucidated. In vitro and in vivo studies suggest that nitric oxide (NO), a potent vasodilator, may partly be responsible for the beneficial effect of HU. This study was designed to determine the effect of oral administration of HU on plasma levels of NO metabolites (NO(x) ) in sickle cell patients (SCP). The results indicate that during steady-state plasma levels of NO(x) were significantly higher in HU-treated patients compared to non HU-treated patients or normal controls (p <.05). In five inpatients in mild pain plasma levels of NO(x) increased significantly after 2 h of HU administration (p <.05); however, in three inpatients in persistent pain with significantly lower baseline NO(x) there was a minimal NO(x) response to HU at 2 h (p <.01). These observations indicate that HU administration is associated with the production of NO in some SCP, but that further study of the pharmacodynamics of this effect is necessary.

Cerebral oximetry in patients with sickle cell disease

BACKGROUND

There is limited information concerning the brain's oxygen supply and demand in patients with sickle cell disease.

DESIGN

We measured near-infrared spectroscopy of brain oxygenation in 27 patients with sickle cell disease regardless of vaso-occlusive crisis, 14 normal healthy controls, and five anaemic patients without sickle cell disease. We also measured pre- and post-transfusion cerebral oximetry in 14 additional sickle cell disease patients who were on transfusion programmes.

RESULTS

The mean cerebral oxygen saturation in the combined steady-state and vaso-occlusive crisis population was found to be significantly lower than that in the controls and in anaemic patients without sickle cell disease (47.7% vs. 61.3%, 59.8%, P < 0.0001). Cerebral oxygen saturation failed to correlate with the haemoglobin concentration (r = 0.51, P > 0.5). However, cerebral oxygen saturation increased from 40.4% to 49.6% (P = 0.01) and correlated significantly with the haemoglobin level (r = 0.553, P = 0.003) in 14 subjects studied before and after transfusions. In seven subjects who received simple transfusions, cerebral oxygen saturation correlated strongly and positively with the haemoglobin level (r = 0.811, P = 0.001) and with percent normal haemoglobin (r = 0.786, P = 0.002), and negatively with abnormal sickle haemoglobin (r = -0.775, P = 0.003). None of these correlations was found to be statistically significant in the seven subjects given exchange transfusions. Cerebral oxygen saturation measured in the sickle cell disease subjects after transfusions was still significantly lower than in the anaemic subjects without sickle cell disease and in the normal controls (49.6% vs. 59.8% and 61.3%, P = 0.001).

CONCLUSIONS

We found that patients with sickle cell disease have subnormal values of cerebral oxygen saturation. Red cell transfusions significantly increased the brain oxygenation in these patients. Cerebral oximetry may be a useful, noninvasive method for assessing the effect of circulating normal red cells in sickle cell patients after transfusions.

Thrombotic microangiopathy following systemic AAV administration is dependent on anti-capsid antibodies

BACKGROUNDSystemic administration of adeno-associated virus (AAV) can trigger life-threatening inflammatory responses, including thrombotic microangiopathy (TMA), acute kidney injury due to atypical hemolytic uremic syndrome-like complement activation, immune-mediated myocardial inflammation, and hepatic toxicity.METHODSWe describe the kinetics of immune activation following systemic AAV serotype 9 (AAV9) administration in 38 individuals following 2 distinct prophylactic immunomodulation regimens. Group 1 received corticosteroids and Group 2 received rituximab plus sirolimus in addition to steroids to prevent anti-AAV antibody formation.RESULTSGroup 1 participants had a rapid increase in immunoglobulin M (IgM) and IgG. Increase in D-dimer, decline in platelet count, and complement activation are indicative of TMA. All Group 1 participants demonstrated activation of both classical and alternative complement pathways, as indicated by depleted C4 and elevated soluble C5b-9, Ba, and Bb antigens. Group 2 patients did not have a significant change in IgM or IgG and had minimal complement activation.CONCLUSIONSThis study demonstrates that TMA in the setting of AAV gene therapy is antibody dependent (classical pathway) and amplified by the alternative complement pathway. Critical time points and interventions are identified to allow for management of immune-mediated events that impact the safety and efficacy of systemic gene therapy.

Burden of mild haemophilia A: Systematic literature review

Introduction

Although the clinical manifestations of severe haemophilia A (HA) are well studied, the challenges, if any, of living with mild HA are not clearly delineated to date.

Aim

To assess available evidence of clinical risks and societal/economic impacts of disease in adult patients with mild HA using a systematic literature review.

Methods

Prespecified study selection criteria were applied in a comprehensive literature search. Included studies varied in design and reported outcomes of interest for adults (≥13 years of age) with mild HA.

Results

Seventeen studies with a total of 3213 patients met eligibility criteria (published or presented in English, 1966‐2017). Most studies were observational, and the outcomes reported were too sparse and dissimilar to support a formal meta‐analysis. Mean annual bleeding rates ranged from 0.44 to 4.5 episodes per patient per year. Quality of life (QoL; SF‐36 General Health) was impacted compared to healthy controls. Health care costs and productivity were seldom assessed and no robust comparisons to healthy controls were available.

Conclusion

Quantifying outcomes for adult patients with mild HA remains challenging, with estimates of key QoL and cost data often based on small data sets and without comparison to population norms. Therefore, the clinical impact of mild haemophilia may be under‐represented and unmet needs may remain unaddressed. As paradigm‐changing therapies for HA emerge, stronger knowledge of mild HA can guide the development of care options that minimize burden and enhance the QoL for this segment of the haemophilia community, and for the haemophilia community in totality.

Effects of hydroxyurea treatment on cerebral oxygenation in adult patients with sickle cell disease: an open-label pilot study

BACKGROUND

In patients with sickle cell disease (SCD), cerebral oxygen saturation (rSO(2)) has been reported to be below normal and to increase after red blood cell transfusion.

OBJECTIVE

This study was designed to determine the effects of long-term and short-term hydroxyurea (HU) treatment on cerebral oxygenation in patients with SCD.

METHODS

This open-label pilot study was conducted at the Department of Anesthesiology and the Center for Sickle Cell Disease, College of Medicine, Howard University, Washington, DC. Adult African American outpatients with SCD and hemoglobin (Hb) genotype HbSS (homozygous sickle Hb) who were receiving long-term (>6 months) HU treatment (15-30 mg/kg . d PO) or who had never received this treatment (control group) were enrolled. Patients in the treated and control groups were matched for age, sex, race, and Hb genotype. Cerebral oximetry (near-infrared spectroscopy) was performed to determine rSO(2) index. In a separate analysis to determine the effects of short-term HU treatment on cerebral oxygenation, hospitalized patients with SCD and vaso-occlusive crisis (VOC)receiving long-term therapy with HU were enrolled. We performed cerebral and pulse (fingernail) oximetry to determine rSO (2)index and arterial oxygen saturation (SpO(2)) after the administration of a single oral dose of HU (500-mg tablet) alone and again after dosing concomitantly with inhaled oxygen.

RESULTS

The study enrolled 11 patients in the HU group (6 women, 5 men; mean [SD] age, 37 [8] years) and 20 controls (8 women, 12 men; mean [SD] age, 35 [6] years). Mean (SD) rSO(2) index was significantly increased (but still low) in patients receiving long-term HU treatment compared with controls (46.1% [6.6%] vs 41.2% [7.6%]; P< 0.025). Hb concentration (9.6 [1.4] g/dL vs 8.5 [1.2] g/dL; P< 0.027), hematocrit (28% [3%] vs 24% [4%]; P < 0.028), and mean corpuscular volume (102% [7%] vs 89% [8%]; P < 0.027) also were significantly higher in the HU group compared with controls. In 8 patients with SCD and VOC (6 men, 2 women; mean [SD] age, 28 [5] years), single-dose HU, either alone or in combination with inhaled oxygen, did not significantly affect cerebral oxygenation, and SpO(2) failed to correlate with rSO(2) index in these patients.

CONCLUSIONS

The results of this open-label pilot study in patients with SCD suggest that the low cerebral oxygenation in these patients is significantly improved but not normalized with long-term HU treatment. A single dose of HU, either alone or in combination with inhaled oxygen, did not appear to influence cerebral oxygenation in patients with VOC.

Immune Responses and Immunosuppressive Strategies for Adeno-Associated Virus-Based Gene Therapy for Treatment of Central Nervous System Disorders: Current Knowledge and Approaches

Adeno-associated viruses (AAVs) are being increasingly used as gene therapy vectors in clinical studies especially targeting central nervous system (CNS) disorders. Correspondingly, host immune responses to the AAV capsid or the transgene-encoded protein have been observed in various clinical and preclinical studies. Such immune responses may adversely impact patients' health, prevent viral transduction, prevent repeated dosing strategies, eliminate transduced cells, and pose a significant barrier to the potential effectiveness of AAV gene therapy. Consequently, multiple immunomodulatory strategies have been used in attempts to limit immune-mediated responses to the vector, enable readministration of AAV gene therapy, prevent end-organ toxicity, and increase the duration of transgene-encoded protein expression. Herein we review the innate and adaptive immune responses that may occur during CNS-targeted AAV gene therapy as well as host- and treatment-specific factors that could impact the immune response. We also summarize the available preclinical and clinical data on immune responses specifically to CNS-targeted AAV gene therapy and discuss potential strategies for incorporating prophylactic immunosuppression regimens to circumvent adverse immune responses.

Biodistribution of Adeno-Associated Virus Gene Therapy Following Cerebrospinal Fluid-Directed Administration

Adeno-associated virus (AAV)-based gene therapies, exemplified by the approved therapy for spinal muscular atrophy, have the potential to deliver disease-course-altering treatments for central nervous system (CNS) indications. However, several clinical trials have reported severe adverse events, including patient deaths following high-dose systemic administration for muscle-directed gene transfer, highlighting the need to explore approaches utilizing lower doses when targeting the CNS. Animal models of disease provide insight into the response to new AAV therapies. However, translation from small to larger animals and eventually to humans is hampered by anatomical and biological differences across the species and their impact on AAV delivery. We performed a literature review of preclinical studies of AAV gene therapy biodistribution following cerebrospinal fluid (CSF) delivery (intracerebroventricular, intra-cisterna magna, and intrathecal lumbar). The reviewed literature varies greatly in the reported biodistribution of AAV following administration into the CSF. Differences between studies, including animal model, vector serotype used, method used to assess biodistribution, and route of administration, among other variables, contribute to differing outcomes and difficulties in translating these preclinical results. For example, only half of the published AAV-based gene therapy studies report vector copy number, the most direct readout following administration of a vector; none of these studies reported details such as the empty:full capsid ratio and quality of encapsidated genome. Analysis of the last decade's literature focusing on AAV-based gene therapies targeting the CNS underscores limitations of the body of knowledge and room for continued research. In particular, there is a need to understand the biodistribution achieved by different CSF-directed routes of administration and determining if specific cell types/structures of interest will be transduced. Our findings point to a clear need for a more systematic approach across the field to align the assessments and elements reported in preclinical research to enable more reliable translation across animal models and into human studies.

Plasma Levels of TNF- in Sickle Cell Patients Receiving Hydroxyurea

Hydroxyurea (HU), a chemotherapeutic agent, used increasingly in the treatment of sickle cell disease (SCD) stimulates the release of a tumor necrosis factor (TNF-alpha) from human macrophages in vitro and the concentration of TNF-alpha is greater than normal in subjects affected by SCD. It is widely accepted that HU may inhibit vaso-occlusive crisis (VOC) by stimulating the production of fetal hemoglobin (HbF) and nitric oxide (NO) in SCD; however, the beneficial effects of HU in vivo may be counteracted by the release of TNF-alpha and, in turn, the expression of a vascular cell adhesion molecule (VCAM-1) on leukocytes. Previous studies have shown that the severity of SCD increases with the leukocyte count. Therefore, we examined the relationship between plasma levels of TNF-alpha and HbF in SCD patients during steady-state (StSt) conditions (in the absence of VOC) and during VOC conditions after the acute administration of HU. Venous blood was collected in SCD patients over 6 h after administering a single dose of HU. Plasma TNF-alpha was found to be greater in SCD subjects than in reported normal adult controls (p<0.05). TNF-alpha in the StSt group was not significantly different than in the VOC group; however, the plasma TNF-alpha tended to greater in the VOC group (p>0.1). An increase in the HbF concentration after acute administration of HU (p<0.01) was not associated with a significant change in plasma TNF-alpha (p>0.1). Contrary to the results of in vitro studies, HU did not increase the plasma concentration of TNF-alpha. These findings suggest that a HU-induced increase in TNF-alpha does not contribute to VOC and sickle cell patients can be counseled that the HU-induced increase in TNF-alpha does not counteract the beneficial effects of HU in SCD.

Effects of hydroxyurea and L-arginine on the production of nitric oxide metabolites in cultures of normal and sickle erythrocytes

Previous in vitro studies suggest that erythrocytes may be a source of nitric oxide (NO) produced by nitric oxide synthase (NOS) or by oxyhemoglobin-mediated oxidation of hydroxyurea (HU). This study was performed to determine the roles of HU and NOS in the production of NO by normal and sickle erythrocytes. Red blood cells (RBCs) from normal adult hemoglobin (HbAA) and homozygous sickle cell subjects (HbSS) were incubated with PBS containing 0.2 mM hydrogen peroxide (control) for 2 h at 37 degrees C in the presence and absence of l-arginine, the substrate for NOS, and with l-arginine plus HU in the presence and absence of l-NMMA, a specific inhibitor of NOS. The nitrate and nitrite metabolites of NO, expressed as [NOx], were measured. [NOx] in the HbAA and HbSS RBC cultures was not significantly different in the presence and absence of 1.0 mM l-arginine (p>0.1). [NOx] in the HbAA and HbSS cultures treated with a clinically relevant dose of HU (1.0 mM) plus 1.0 mM l-arginine was significantly greater than that in controls incubated with PBS and with l-arginine p < 0.01. However, [NOx] in the HbAA and HbSS cultures treated with 50 microg/ml l-NMMA was not significantly different than that in the cultures treated with HU plus l-arginine in the absence of l-NMMA. These findings suggest that NOx production by erythrocytes may be increased by treatment with HU and may not be decreased by inhibiting NOS. Therefore, we conclude that a therapeutic dose of HU may increase the plasma concentration of NO by a mechanism that does not require erythrocytes NOS activity.

A phase I dose-escalation study of MEDI-575, a PDGFRα monoclonal antibody, in adults with advanced solid tumors

Purpose

The purpose of the study was to evaluate safety and determine the maximum tolerated dose (MTD) of MEDI-575, a fully human monoclonal antibody that selectively binds to platelet-derived growth factor receptor-α (PDGFRα), in patients with advanced solid tumors.

Methods

This phase I multicenter, open-label, single-arm study enrolled adults in a 3 + 3 dose escalation design to receive MEDI-575 (3, 6, 9, 12, or 15 mg/kg) once weekly (QW) until toxicity or disease progression occurred. One 0.5-mg/kg dose was given before the first dose in the 3-mg/kg cohort to determine pharmacokinetics (PK) and pharmacodynamics under unsaturated conditions. After completion of dose escalation in the QW cohorts, patients were enrolled in two additional cohorts and received MEDI-575 25 or 35 mg/kg every 3 weeks (Q3W). Secondary measures included assessments of PK, immunogenicity, and antitumor activity.

Results

A total of 35 patients received MEDI-575 QW (n = 23) or Q3W (n = 12). Most treatment-related adverse events were grade 1 or 2 in severity across all dose levels, with fatigue (n = 12) and nausea (n = 8) being reported most frequently. With no reports of dose-limiting toxicities (DLTs), the MTD was not reached. MEDI-575 exhibited a nonlinear PK profile and increased plasma platelet-derived growth factor-AA levels in a dose-dependent manner with limited immunogenicity. Stable disease was reported as the best tumor response in 9 of 29 evaluable patients; however, no objective responses were reported.

Conclusion

Administration of MEDI-575 QW or Q3W resulted in a favorable safety profile, including a lack of DLTs, but without evidence of antitumor activity in patients with refractory solid tumors.

SLC13A5 Deficiency Disorder: From Genetics to Gene Therapy

Epileptic encephalopathies may arise from single gene variants. In recent years, next-generation sequencing technologies have enabled an explosion of gene identification in monogenic epilepsies. One such example is the epileptic encephalopathy SLC13A5 deficiency disorder, which is caused by loss of function pathogenic variants to the gene SLC13A5 that results in deficiency of the sodium/citrate cotransporter. Patients typically experience seizure onset within the first week of life and have developmental delay and intellectual disability. Current antiseizure medications may reduce seizure frequency, yet more targeted treatments are needed to address the epileptic and non-epileptic features of SLC13A5 deficiency disorder. Gene therapy may offer hope to these patients and better clinical outcomes than current available treatments. Here, we discuss SLC13A5 genetics, natural history, available treatments, potential outcomes and assessments, and considerations for translational medical research for an AAV9-based gene replacement therapy.

Corneal stem cells niche and homeostasis impacts in regenerative medicine; concise review

The limbal stem cells niche (LSCN) is an optimal microenvironment that provides the limbal epithelial stem cells (LESCs) and strictly regulates their proliferation and differentiation. Disturbing the LSCN homeostasis can lead to limbal stem cell dysfunction (LSCD) and subsequent ocular surface aberrations, such as corneal stromal inflammation, persistent epithelial defects, corneal neovascularisation, lymphangiogenesis, corneal opacification, and conjunctivalization. As ocular surface disorders are considered the second main cause of blindness, it becomes crucial to explore different therapeutic strategies for restoring the functions of the LSCN. A major limitation of corneal transplantation is the current shortage of donor tissue to meet the requirements worldwide. In this context, it becomes mandatory to find an alternative regenerative medicine, such as using cultured limbal epithelial/stromal stem cells, inducing the production of corneal like cells by using other sources of stem cells, and using tissue engineering methods aiming to produce the three-dimensional (3D) printed cornea. Limbal epithelial stem cells have been considered the magic potion for eye treatment. Epithelial and stromal stem cells in the limbal niche hold the responsibility of replenishing the corneal epithelium. These stem cells are being used for transplantation to maintain corneal epithelial integrity and ultimately sustain optimal vision. In this review, we summarised the characteristics of the LSCN and their current and future roles in restoring corneal homeostasis in eyes with LSCD.

Transcriptomic Profiling of Human Limbus-Derived Stromal/Mesenchymal Stem Cells-Novel Mechanistic Insights into the Pathways Involved in Corneal Wound Healing

Limbus-derived stromal/mesenchymal stem cells (LMSCs) are vital for corneal homeostasis and wound healing. However, despite multiple pre-clinical and clinical studies reporting the potency of LMSCs in avoiding inflammation and scarring during corneal wound healing, the molecular basis for the ability of LMSCs remains unknown. This study aimed to uncover the factors and pathways involved in LMSC-mediated corneal wound healing by employing RNA-Sequencing (RNA-Seq) in human LMSCs for the first time. We characterized the cultured LMSCs at the stages of initiation (LMSC−P0) and pure population (LMSC−P3) and subjected them to RNA-Seq to identify the differentially expressed genes (DEGs) in comparison to native limbus and cornea, and scleral tissues. Of the 28,000 genes detected, 7800 DEGs were subjected to pathway-specific enrichment Gene Ontology (GO) analysis. These DEGs were involved in Wnt, TGF-β signaling pathways, and 16 other biological processes, including apoptosis, cell motility, tissue remodeling, and stem cell maintenance, etc. Two hundred fifty-four genes were related to wound healing pathways. COL5A1 (11.81 ± 0.48) and TIMP1 (20.44 ± 0.94) genes were exclusively up-regulated in LMSC−P3. Our findings provide new insights involved in LMSC-mediated corneal wound healing.

Arterialization of Venous Blood for Differentiation of Sickle Cell Subjects in Vaso-occlusive Crisis

These studies were designed as two experiments. Experiment 1 was performed to validate the hypothesis that oxygen saturation of the venous blood may be a marker for vaso-occlusive crisis (VOC) in sickle cell patients undergoing hydroxyurea (HU) treatments. Experiment 2 was performed to test the hypothesis that an acute increase in the blood nitric oxide (NO) concentration by administering HU modulates the perception of pain in sickle cell subjects in VOC. The percent saturations of oxyhemoglobin (%O<PRE>2</PRE>Hb), reduced hemoblogin (%RHb), carboxy-hemoglobin (%COHb), met-hemoglobin (%MHb), fetal hemoglobin (HbF), and nitric oxide metabolites were measured in venous blood samples collected from sickle cell disease (SCD) who were on and off HU and O<PRE>2</PRE> at steady state and during VOC. The results showed the ratio of %O<PRE>2</PRE>Hb/RHb in VOC+HU was significantly higher than patients in the steady state who were on and off of HU (p<0.05). The %COHb was higher in all SCD groups, %COHb values were significantly different in SCD at steady state who were on HU. HU and O<PRE>2</PRE> treatment did not play important role on venous blood %O<PRE>2</PRE>Hb and pain scores in SCD during VOC. A single oral dose of HU was associated with a significant increase in the venous concentration of nitric oxide metabolites (NOx), p<0.05. These findings suggest that the ratio %O<PRE>2</PRE>Hb/RHb in venous blood and pain scores differentiate HU-untreated and HU-treated at steady state subjects from HU-treated subjects in VOC; however, the acute increase in venous NOx produced by administering HU to HU-treated subjects in VOC does not explain this difference.

Bacillus anthracis endospores regulate ornithine decarboxylase and inducible nitric oxide synthase through ERK1/2 and p38 mitogen-activated protein kinases

Interactions between Bacillus anthracis (B. anthracis) and host cells are of particular interest given the implications of anthrax as a biological weapon. Inhaled B. anthracis endospores encounter alveolar macrophages as the first line of defense in the innate immune response. Yet, the consequences of this interaction remain unclear. We have demonstrated that B. anthracis uses arginase, inherent in the endospores, to reduce the ability of macrophages to produce nitric oxide ((•)NO) from inducible nitric oxide synthase (NOS2) by competing for L-arginine, producing L-ornithine at the expense of (•)NO. In the current study, we used genetically engineered B. anthracis endospores to evaluate the contribution of germination and the lethal toxin (LT) in mediating signaling pathways responsible for the induction of NOS2 and ornithine decarboxylase (ODC), which is the rate-limiting enzyme in the conversion of L-ornithine into polyamines. We found that induction of NOS2 and ODC expression in macrophages exposed to B. anthracis occurs through the activation of p38 and ERK1/2 MAP kinases, respectively. Optimal induction of NOS2 was observed following exposure to germination-competent endospores, whereas ODC induction occurred irrespective of the endospores' germination capabilities and was more prominent in macrophages exposed to endospores lacking LT. Our findings suggest that activation of kinase signaling cascades that determine macrophage defense responses against B. anthracis infection occurs through distinct mechanisms.

Effect of transfusion on cerebral oxygenation, flow velocity in a patient with sickle cell anemia and Moyamoya disease: a case report

Vascular occlusive diseases affect brain blood flow, brain metabolism and are associated with arterial ischemic stroke. This study was designed to measure the brain blood flow velocity, brain oxygenation, hemoglobin concentrations, hematocrit, and cell free hemoglobin at pre- and post-exchange red cell transfusion in an 18 year old male patient with sickle cell disease and moyamoya syndrome (MMS). Exchange transfusion increased cerebral oxygen saturation 12%, total hemoglobin concentration 2%, hemoglobin AA 80%, and reduced sickle (SS) hemoglobin 12%, arterializations 33%, and cell free hemoglobin 33%. Brain blood flow velocity values were unaffected by transfusion. These observations suggest that exchange transfusion increases the hemoglobin carrying capacity and reduces sickle hemoglobin and shunting of blood, which may improve the peripheral and cerebral oxygenation. Transfusion did not affect the brain blood flow in this patient. Therefore the risk of transient ischemic attack and arterial ischemic stroke from mms still exist.