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1.
Blood Adv ; 5(1): 207-215, 2021 01 12.
Article in English | MEDLINE | ID: mdl-33570644

ABSTRACT

We aimed to identify predictors of outcomes and survival in patients living in 4 major metropolitan areas who had sickle cell disease (SCD) and COVID-19 to inform best approaches to prevention and care. Data were collected at baseline and during the clinical course in SCD patients diagnosed with COVID-19 in four COVID-19 epicenters. Patients were followed up posthospital discharge for up to 3 months. Of sixty-six SCD patients with COVID-19, fifty patients (75%) required hospitalization, and seven died (10.6%). Patients with preexisting kidney disease (chronic kidney disease) were more likely to be hospitalized. The most common presenting symptom was vaso-occlusive pain. Acute chest syndrome occurred in 30 (60%) of the 50 hospitalized patients and in all who died. Older age and histories of pulmonary hypertension, congestive heart failure, chronic kidney disease, and stroke were more prevalent in patients who died, as were higher creatinine, lactate dehydrogenase, and D-dimer levels. Anticoagulation use while inpatient was twice less common in patients who died. All deaths occurred in individuals not taking hydroxyurea or any other SCD-modifying therapy. Patients with SCD and COVID-19 exhibited a broad range of disease severity. We cannot definitively state that the overall mortality is higher in patients with SCD, although our case fatality rate was ∼10% compared with ∼3% in the general population, despite a median age of 34 years. Individuals with SCD aged >50 years, with preexisting cardiopulmonary, renal disease, and/or stroke not receiving hydroxyurea, who present with high serum creatinine, lactate dehydrogenase, and D-dimer levels, are at higher risk of death, irrespective of genotype or sex.


Subject(s)
Anemia, Sickle Cell/complications , COVID-19/complications , Acute Chest Syndrome/blood , Acute Chest Syndrome/complications , Acute Chest Syndrome/mortality , Acute Chest Syndrome/therapy , Adult , Anemia, Sickle Cell/blood , Anemia, Sickle Cell/mortality , Anemia, Sickle Cell/therapy , Antisickling Agents/therapeutic use , COVID-19/blood , COVID-19/mortality , COVID-19/therapy , Disease Progression , Female , Fibrin Fibrinogen Degradation Products/analysis , Humans , Hydroxyurea/therapeutic use , Male , Risk Factors , SARS-CoV-2/isolation & purification , Young Adult
2.
BMJ Open ; 9(10): e031525, 2019 10 28.
Article in English | MEDLINE | ID: mdl-31662390

ABSTRACT

OBJECTIVES: The aim of this study was to characterise the resources and challenges for surgical care and referrals at health centres (HCs) in South Wollo Zone, Ethiopia. SETTING: Eight primary HCs in South Wollo Zone, Ethiopia. PARTICIPANTS: Eight health officers and nurses staffing eight HCs completed a survey. DESIGN: The study was a survey-based, cross-sectional assessment of HCs in South Wollo Zone, Ethiopia and data were collected over a 30-day period from November 2014 to January 2015. PRIMARY AND SECONDARY OUTCOME MEASURES: Survey assessed human and material resources, diagnostic capabilities and challenges and patient-reported barriers to care. RESULTS: Eight HCs had an average of 18 providers each, the majority of which were nurses (62.2%) and health officers (20.7%). HCs had intermittent availability of clean water, nasogastric tubes, rectal tubes and suturing materials, none of them had any form of imaging. A total of 168 surgical patients were seen at the 8 HCs; 58% were referred for surgery. Most common diagnoses were trauma/burns (42%) and need for caesarean section (9%). Of those who did not receive surgery, 32 patients reported specific barriers to obtaining care (91.4%). The most common specific barriers were patients not being decision makers to have surgery, lack of family/social support and inability to afford hospital fees. CONCLUSIONS: HCs in South Wollo Zone, Ethiopia are well-staffed with nurses and health officers, however they face a number of diagnostic and treatment challenges due to lack of material resources. Many patients requiring surgery receive initial diagnosis and care at HCs; sociocultural and financial factors commonly prohibit these patients from receiving surgery. Further study is needed to determine how such delays may impact patient outcomes. Improving material resources at HCs and exploring community and family perceptions of surgery may enable more streamlined access to surgical care and prevent delays.


Subject(s)
Cesarean Section/statistics & numerical data , Equipment and Supplies/supply & distribution , Health Services Accessibility , Health Workforce/statistics & numerical data , Referral and Consultation , Surgical Procedures, Operative/statistics & numerical data , Wounds and Injuries/surgery , Adult , Appendicitis/surgery , Diagnostic Imaging/instrumentation , Ethiopia , Health Facilities , Health Resources , Humans , Intestinal Obstruction/surgery , Middle Aged , Midwifery , Nurses , Peptic Ulcer/surgery , Surveys and Questionnaires , Time-to-Treatment , Water Supply , Young Adult
3.
Article in English | MEDLINE | ID: mdl-29133571

ABSTRACT

The recommended management of inhalational anthrax, a high-priority bioterrorist threat, includes antibiotics and antitoxins. Obiltoxaximab, a chimeric monoclonal antibody against anthrax protective antigen (PA), is licensed under the U.S. Food and Drug Administration's (FDA's) Animal Rule for the treatment of inhalational anthrax. Because of spore latency, disease reemergence after treatment cessation is a concern, and there is a need to understand the development of endogenous protective immune responses following antitoxin-containing anthrax treatment regimens. Here, acquired protective immunity was examined in New Zealand White (NZW) rabbits challenged with a targeted lethal dose of Bacillus anthracis spores and treated with antibiotics, obiltoxaximab, or a combination of both. Survivors of the primary challenge were rechallenged 9 months later and monitored for survival. Survival rates after primary and rechallenge for controls and animals treated with obiltoxaximab, levofloxacin, or a combination of both were 0, 65, 100, and 95%, and 0, 100, 95, and 89%, respectively. All surviving immune animals had circulating antibodies to PA and serum toxin-neutralizing titers prior to rechallenge. Following rechallenge, systemic bacteremia and toxemia were not detected in most animals, and the levels of circulating anti-PA IgG titers increased starting at 5 days postrechallenge. We conclude that treatment with obiltoxaximab, alone or combined with antibiotics, significantly improves the survival of rabbits that received a lethal inhalation B. anthracis spore challenge dose and does not interfere with the development of immunity. Survivors of primary challenge are protected against reexposure, have rare incidents of systemic bacteremia and toxemia, and have evidence of an anamnestic response.


Subject(s)
Anthrax , Anti-Bacterial Agents , Antibodies, Monoclonal , Antitoxins , Bacillus anthracis , Levofloxacin , Respiratory Tract Infections , Spores, Bacterial , Animals , Female , Male , Rabbits , Anthrax/immunology , Anthrax/microbiology , Anthrax/mortality , Anthrax/prevention & control , Anti-Bacterial Agents/pharmacology , Antibodies, Bacterial/biosynthesis , Antibodies, Monoclonal/pharmacology , Antigens, Bacterial/blood , Antigens, Bacterial/immunology , Antitoxins/pharmacology , Bacillus anthracis/drug effects , Bacillus anthracis/immunology , Bacillus anthracis/pathogenicity , Bacterial Toxins/antagonists & inhibitors , Bacterial Toxins/blood , Bacterial Toxins/immunology , Drug Therapy, Combination , Immunization, Passive/methods , Immunoglobulin G/biosynthesis , Immunologic Memory/drug effects , Levofloxacin/pharmacology , Random Allocation , Respiratory Tract Infections/immunology , Respiratory Tract Infections/microbiology , Respiratory Tract Infections/mortality , Respiratory Tract Infections/prevention & control , Spores, Bacterial/drug effects , Spores, Bacterial/immunology , Spores, Bacterial/pathogenicity , Survival Analysis
8.
Clin Ther ; 38(9): 2083-2097.e7, 2016 Sep.
Article in English | MEDLINE | ID: mdl-27568215

ABSTRACT

PURPOSE: This report describes the safety, immunogenicity, and pharmacokinetic results of obiltoxaximab treatment in healthy subjects from 5 clinical trials. METHODS: Healthy men and women were enrolled in randomized, double-blind studies of obiltoxaximab versus placebo (studies 1-3), an open-label, parallel-group study of obiltoxaximab alone versus obiltoxaximab and ciprofloxacin (study 4), or a randomized, double-blind, placebo-controlled study involving administration of a second dose of obiltoxaximab 13 or 119 days after an initial dose (study 5). Obiltoxaximab was administered intravenously in all studies. The safety profile was characterized by physical examinations, including focused examinations of the skin and infusion sites; study drug infusion discontinuations; and assessment of adverse events, vital signs, electrocardiographic findings, laboratory parameters, and immunogenicity. Studies 3 to 5 were the primary safety profile studies. Pharmacokinetic parameters were calculated using noncompartmental methods. FINDINGS: Results of 2 multiple dose studies (studies 1 and 2) revealed that obiltoxaximab exposure increased proportionally. Pharmacokinetic results were consistent across studies. After administration of 16 mg/kg of obiltoxaximab, serum concentrations decreased in a biexponential or multiexponential fashion with a terminal half-life of 17 to 23 days. Mean volume of distribution was approximately 6.3 to 7.5 L, suggesting obiltoxaximab distribution outside the vascular compartment and potentially into tissues. Mean systemic clearance was approximately 0.27 L/d, suggesting that hepatic metabolism and/or renal excretion are not critical to obiltoxaximab elimination. Obiltoxaximab was generally well tolerated. Hypersensitivity reactions were the most common adverse reactions in the safety profile clinical trials, occurring in 34 of 320 subjects (10.6%) receiving obiltoxaximab and 4 of 70 subjects (5.7%) receiving placebo. The most common adverse events were headache, pruritus, upper respiratory tract infection, cough, infusion site swelling, bruising and/or pain, nasal congestion, urticaria, and extremity pain. Of the 320 subjects in the primary safety profile studies who received ≥1 dose of 16 mg/kg of obiltoxaximab, 8 (2.5%) tested positive for a exposure-emergent antiobiltoxaximab response; however, quantitative titers were low (1:20-1:320). IMPLICATIONS: On the basis of consistent results of 5 clinical trials in healthy volunteers, the pharmacokinetic properties of obiltoxaximab after a 16-mg/kg IV infusion can be considered adequately characterized, a criteria of the Animal Rule. Obiltoxaximab appears to be generally well tolerated. ClinicalTrials.gov identifiers: NCT00829582, NCT01453907, NCT01929226, NCT01952444, NCT01932242.


Subject(s)
Antibodies, Monoclonal/adverse effects , Antibodies, Monoclonal/blood , Antitoxins/adverse effects , Antitoxins/blood , Adolescent , Adult , Aged , Antibodies, Monoclonal/administration & dosage , Antitoxins/administration & dosage , Area Under Curve , Double-Blind Method , Drug Administration Schedule , Drug Hypersensitivity/etiology , Female , Half-Life , Headache/chemically induced , Healthy Volunteers , Humans , Infusions, Intravenous , Male , Middle Aged , Young Adult
9.
Antimicrob Agents Chemother ; 60(10): 5796-805, 2016 10.
Article in English | MEDLINE | ID: mdl-27431219

ABSTRACT

The Centers for Disease Control and Prevention recommend adjunctive antitoxins when systemic anthrax is suspected. Obiltoxaximab, a monoclonal antibody against protective antigen (PA), is approved for treatment of inhalational anthrax in combination with antibiotics and for prophylaxis when alternative therapies are not available. The impact of toxin neutralization with obiltoxaximab during pre- and postexposure prophylaxis was explored, and efficacy results that supported the prophylaxis indication are presented here. New Zealand White rabbits and cynomolgus macaques received obiltoxaximab as a single intramuscular or intravenous dose of 2 to 16 mg/kg of body weight at various times relative to Bacillus anthracis aerosol spore challenge. The primary endpoint was survival, and effect of treatment timing was explored. In rabbits, obiltoxaximab administration 9 h postchallenge singly or combined with a 5-day levofloxacin regimen protected 89% to 100% of animals compared to 33% with levofloxacin monotherapy. In cynomolgus macaques, a single intramuscular dose of 16 mg/kg obiltoxaximab led to 100% survival when given 1 to 3 days preexposure and 83% to 100% survival when given 18 to 24 h postexposure and prior to systemic bacteremia onset. Obiltoxaximab administration after bacteremia onset resulted in lower (25% to 50%) survival rates reflective of treatment setting. Prophylactic administration of obiltoxaximab before spore challenge or to spore-challenged animals before systemic bacterial dissemination is efficacious in promoting survival, ameliorating toxemia, and inhibiting bacterial spread to the periphery.


Subject(s)
Anthrax/mortality , Anthrax/prevention & control , Antibodies, Monoclonal/pharmacology , Antitoxins/pharmacology , Bacillus anthracis/pathogenicity , Respiratory Tract Infections/mortality , Respiratory Tract Infections/prevention & control , Animals , Anthrax/drug therapy , Anti-Bacterial Agents/administration & dosage , Anti-Bacterial Agents/pharmacokinetics , Anti-Bacterial Agents/pharmacology , Antibodies, Monoclonal/administration & dosage , Antibodies, Monoclonal/pharmacokinetics , Antitoxins/administration & dosage , Bacillus anthracis/drug effects , Bacteremia/drug therapy , Bacteremia/microbiology , Disease Models, Animal , Female , Injections, Intramuscular , Injections, Intravenous , Macaca fascicularis , Male , Post-Exposure Prophylaxis , Pre-Exposure Prophylaxis , Rabbits , Respiratory Tract Infections/drug therapy , Survival Rate
10.
Antimicrob Agents Chemother ; 60(10): 5787-95, 2016 10.
Article in English | MEDLINE | ID: mdl-27431222

ABSTRACT

Inhalational anthrax has high mortality even with antibiotic treatment, and antitoxins are now recommended as an adjunct to standard antimicrobial regimens. The efficacy of obiltoxaximab, a monoclonal antibody against anthrax protective antigen (PA), was examined in multiple studies conducted in two animal models of inhalational anthrax. A single intravenous bolus of 1 to 32 mg/kg of body weight obiltoxaximab or placebo was administered to New Zealand White rabbits (two studies) and cynomolgus macaques (4 studies) at disease onset (significant body temperature increase or detection of serum PA) following lethal challenge with aerosolized Bacillus anthracis spores. The primary endpoint was survival. The relationship between efficacy and disease severity, defined by pretreatment bacteremia and toxemia levels, was explored. In rabbits, single doses of 1 to 16 mg/kg obiltoxaximab led to 17 to 93% survival. In two studies, survival following 16 mg/kg obiltoxaximab was 93% and 62% compared to 0% and 0% for placebo (P = 0.0010 and P = 0.0013, respectively). Across four macaque studies, survival was 6.3% to 78.6% following 4 to 32 mg/kg obiltoxaximab. In two macaque studies, 16 mg/kg obiltoxaximab reduced toxemia and led to survival rates of 31%, 35%, and 47% versus 0%, 0%, and 6.3% with placebo (P = 0.0085, P = 0.0053, P = 0.0068). Pretreatment bacteremia and toxemia levels inversely correlated with survival. Overall, obiltoxaximab monotherapy neutralized PA and increased survival across the range of disease severity, indicating clinical benefit of toxin neutralization with obiltoxaximab in both early and late stages of inhalational anthrax.


Subject(s)
Anthrax/drug therapy , Anti-Bacterial Agents/pharmacology , Antibodies, Monoclonal/pharmacology , Antitoxins/pharmacology , Respiratory Tract Infections/drug therapy , Animals , Anthrax/etiology , Anthrax/mortality , Anti-Bacterial Agents/pharmacokinetics , Antibodies, Monoclonal/pharmacokinetics , Female , Macaca fascicularis , Male , Rabbits , Respiratory Tract Infections/etiology , Respiratory Tract Infections/mortality , Survival Rate , Treatment Outcome
12.
Clin Transplant ; 29(2): 134-41, 2015 Feb.
Article in English | MEDLINE | ID: mdl-25430554

ABSTRACT

Sarcopenia, or loss of skeletal muscle mass, is associated with increased mortality and morbidity in liver transplant (LT) candidates. Six-minute walk distance (6MWD) and health-related quality of life (HRQOL) as assessed by short form 36 scores (SF-36) also impact clinical outcomes in these patients. This study explored the relationship between the sarcopenia, 6MWD, and HRQOL in LT candidates. Sarcopenia was evaluated based on skeletal muscle mass index (SMI) quantified from abdominal computed tomography. Patients were followed until death, removal from the wait list or the end of the study period. Two hundred and thirteen patients listed for LT were included. The mean SMI, 6MWD and mean gait speed were 54.3 ± 9.7, 370.5 m and 1 m/s, respectively. Sarcopenia was noted in 22.2% of LT candidates. There was no correlation between sarcopenia, 6MWD, and SF-36 scores. The 6MWD, but not sarcopenia, was an independent predictor of mortality (hazard ratio = 2.1 [0.9-4.7]). In summary, sarcopenia did not emerge as a significant predictor of waitlist mortality and also failed to correlate with either functional capacity or HRQOL in LT candidates. In patients with ESLD awaiting LT, 6MWD appears to be a more useful prognostic indicator than the presence of sarcopenia.


Subject(s)
Liver Transplantation/psychology , Quality of Life , Sarcopenia/psychology , Transplants , Walking/physiology , Body Mass Index , Exercise Test , Female , Humans , Male , Middle Aged , Prognosis , Retrospective Studies , Sarcopenia/physiopathology
13.
Radiol Case Rep ; 9(1): e00031, 2014.
Article in English | MEDLINE | ID: mdl-27141243

ABSTRACT

We present a case of focal increased intrahepatic radiotracer activity on 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) in a patient with lymphoma and superior vena cava (SVC) obstruction, a false positive for malignancy. Contrast-enhanced computed tomography (CT) demonstrated an enhancing region of geographic focal hypoattenuation in the liver along the falciform, corresponding to the region of increased radiotracer activity on FDG-PET, with marked narrowing of the superior vena cava and resultant collateral venous pathways to the portal vein via paraumbilical veins. CT followup demonstrated stability of the hepatic abnormality, and no lesion was evident on ultrasound, suggesting that the finding on PET-CT represented a false positive for malignancy in this patient with known SVC obstruction. In patients with SVC obstruction, radiologists should consider this phenomenon of anomalous hepatic uptake along the falciform as a source of possible false positives for malignancy on PET.

14.
J Trauma Stress ; 26(6): 767-71, 2013 Dec.
Article in English | MEDLINE | ID: mdl-24243652

ABSTRACT

Experiences of abuse during childhood or military service may increase women veterans' risk for intimate partner violence (IPV) victimization. This study examined the relative impact of 3 forms of interpersonal violence exposure (childhood physical abuse [CPA], childhood sexual abuse [CSA], and unwanted sexual experiences during military service) and demographic and military characteristics on past-year IPV among women veterans. Participants were 160 female veteran patients at Veterans Afffairs hospitals in New England who completed a paper-and-pencil mail survey that included validated assessments of past-year IPV and previous interpersonal violence exposures. Women who reported CSA were 3.06 times, 95% confidence interval (CI) [1.14, 8.23], more likely to report past-year IPV relative to women who did not experience CSA. Similarly, women who reported unwanted sexual experiences during military service were 2.33 times, 95% CI [1.02, 5.35], more likely to report past-year IPV compared to women who did not report such experiences. CPA was not associated with IPV risk. Having less education and having served in the Army (vs. other branches) were also associated with greater risk of experiencing IPV in the past year. Findings have implications for assisting at risk women veterans in reducing their risk for IPV through detection and intervention efforts.


Subject(s)
Adult Survivors of Child Abuse/statistics & numerical data , Spouse Abuse/statistics & numerical data , Veterans/statistics & numerical data , Adult , Battered Women/statistics & numerical data , Child , Child Abuse, Sexual/statistics & numerical data , Educational Status , Female , Humans , Middle Aged , Military Personnel/statistics & numerical data , Risk Factors , Sex Offenses/statistics & numerical data , Surveys and Questionnaires
15.
Planta ; 237(1): 189-210, 2013 Jan.
Article in English | MEDLINE | ID: mdl-23007552

ABSTRACT

In recent years, there has been a significant increase in the number of completely sequenced plant genomes. The comparison of fully sequenced genomes allows for identification of new gene family members, as well as comprehensive analysis of gene family evolution. The aldehyde dehydrogenase (ALDH) gene superfamily comprises a group of enzymes involved in the NAD(+)- or NADP(+)-dependent conversion of various aldehydes to their corresponding carboxylic acids. ALDH enzymes are involved in processing many aldehydes that serve as biogenic intermediates in a wide range of metabolic pathways. In addition, many of these enzymes function as 'aldehyde scavengers' by removing reactive aldehydes generated during the oxidative degradation of lipid membranes, also known as lipid peroxidation. Plants and animals share many ALDH families, and many genes are highly conserved between these two evolutionarily distinct groups. Conversely, both plants and animals also contain unique ALDH genes and families. Herein we carried out genome-wide identification of ALDH genes in a number of plant species-including Arabidopsis thaliana (thale crest), Chlamydomonas reinhardtii (unicellular algae), Oryza sativa (rice), Physcomitrella patens (moss), Vitis vinifera (grapevine) and Zea mays (maize). These data were then combined with previous analysis of Populus trichocarpa (poplar tree), Selaginella moellindorffii (gemmiferous spikemoss), Sorghum bicolor (sorghum) and Volvox carteri (colonial algae) for a comprehensive evolutionary comparison of the plant ALDH superfamily. As a result, newly identified genes can be more easily analyzed and gene names can be assigned according to current nomenclature guidelines; our goal is to clarify previously confusing and conflicting names and classifications that might confound results and prevent accurate comparisons between studies.


Subject(s)
Aldehyde Dehydrogenase/genetics , Multigene Family , Plant Proteins/genetics , Plants/genetics , Aldehyde Dehydrogenase/metabolism , Aldehydes/metabolism , Animals , Arabidopsis/enzymology , Arabidopsis/genetics , Bryopsida/enzymology , Bryopsida/genetics , Chlamydomonas reinhardtii/enzymology , Chlamydomonas reinhardtii/genetics , Chromosome Mapping , Chromosomes, Plant/genetics , Evolution, Molecular , Genome, Plant/genetics , Genomics/methods , Oryza/enzymology , Oryza/genetics , Plant Proteins/metabolism , Plants/classification , Plants/enzymology , Populus/enzymology , Populus/genetics , Selaginellaceae/enzymology , Selaginellaceae/genetics , Sorghum/enzymology , Sorghum/genetics , Terminology as Topic , Vitis/enzymology , Vitis/genetics , Volvox/enzymology , Volvox/genetics , Zea mays/enzymology , Zea mays/genetics
16.
Bioorg Med Chem ; 16(23): 10061-74, 2008 Dec 01.
Article in English | MEDLINE | ID: mdl-18952446

ABSTRACT

Peptidyl alpha-hydroxylating monooxygenase (PHM) functions in vivo towards the biosynthesis of alpha-amidated peptide hormones in mammals and insects. PHM is a potential target for the development of inhibitors as drugs for the treatment of human disease and as insecticides for the management of insect pests. We show here that relatively simple ground state analogs of the PHM substrate hippuric acid (C(6)H(5)-CO-NH-CH(2)-COOH) inhibit the enzyme with K(i) values as low as 0.5microM. Substitution of sulfur atom(s) into the hippuric acid analog increases the affinity of PHM for the inhibitor. Replacement of the acetylglycine moiety, -CO-NH-CH(2)-COOH with an S-(thioacetyl)thioglycolic acid moiety, -CS-S-CH(2)-COOH, yields compounds with the highest PHM affinity. Both S-(2-phenylthioacetyl)thioglycolate and S-(4-ethylthiobenzoyl)thioglycolic acid inhibit the proliferation of cultured human prostate cancer cells at concentrations >100-fold excess of their respective K(i) values. Comparison of K(i) values between mammalian PHM and insect PHM shows differences in potency suggesting that a PHM-based insecticide with limited human toxicity can be developed.


Subject(s)
Enzyme Inhibitors/chemistry , Hippurates/chemistry , Hippurates/pharmacology , Insecticides/chemistry , Mixed Function Oxygenases/antagonists & inhibitors , Multienzyme Complexes/antagonists & inhibitors , Animals , Antineoplastic Agents/chemical synthesis , Antineoplastic Agents/chemistry , Antineoplastic Agents/pharmacology , Enzyme Inhibitors/chemical synthesis , Enzyme Inhibitors/pharmacology , Hippurates/chemical synthesis , Humans , Inhibitory Concentration 50 , Insecticides/metabolism , Insecticides/pharmacology , Mixed Function Oxygenases/metabolism , Models, Molecular , Multienzyme Complexes/metabolism , Rats , Structure-Activity Relationship , Tumor Cells, Cultured
17.
Anal Biochem ; 323(2): 242-6, 2003 Dec 15.
Article in English | MEDLINE | ID: mdl-14656531

ABSTRACT

Herein, we present a new enzyme-linked spectrophotometric assay for glyoxylate that detects glyoxylate via the formation of an intensely colored formazan. This glyoxylate-specific assay is reliant upon the enzymatic conversion of glyoxylate to oxaloacetate coupled to the reduction of oxidized nicotinamide adenine dinucleotide to reduced nicotinamide adenine dinucleotide (NADH). The NADH-dependent reduction of a tetrazolium to the formazan enables the measurement of nanomole quantities of glyoxylate in an assay that is amenable to high-throughput screening methods. Assay validation was accomplished using two methods for glyoxylate generation, the base-catalyzed N-dealkylation of alpha-hydroxyhippurate to benzamide and glyoxylate and the oxidative cleavage of the glycyl Calpha-N bond in N-benzoylglycine (hippurate) by peptidylglycine alpha-amidating monooxygenase to again yield benzamide and glyoxylate. For both reactions, analysis of benzamide produced by reverse-phase high-performance liquid chromatography compared with glyoxylate measured using our glyoxylate assay showed a 1:1 molar ratio of benzamide to glyoxylate. These results indicate that the enzyme-linked spectrophotometric assay can quantitatively measure submicromole quantities of glyoxylate.


Subject(s)
Glyoxylates/analysis , Spectrophotometry/methods , Chromatography, High Pressure Liquid , Kinetics , Malate Dehydrogenase/metabolism , Malate Synthase/metabolism
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