tag:blogger.com,1999:blog-30416082872158183682024-02-08T12:00:39.240-08:00MYOGLOBIN RESEARCHUnknownnoreply@blogger.comBlogger16125tag:blogger.com,1999:blog-3041608287215818368.post-45984937505821565732016-11-01T10:13:00.001-07:002016-11-01T10:13:10.148-07:00High Level of Serum Myoglobin in Human Intracerebral Hemorrhage: Implications for Large Hematoma Volume and Growth <div class="doi">
</div>
<h4>
Background</h4>
<div id="sp0010">
Myoglobin and cardiac troponin T are often elevated in patients with ischemic stroke. However, the association, if any, between both myoglobin and troponin T levels and hematoma volume in patients with intracerebral hemorrhage remains to be established. We investigate the possible relationship between admission myoglobin and troponin T levels and hematoma volume and growth.</div>
<h4 id="absSec_2">
Methods</h4>
<div id="sp0015">
A total of 143 patients with intracerebral hemorrhage admitted within 72 hours after symptom onset were divided into 4 groups according to the quartile of myoglobin levels. The information of hematoma was assessed with computed tomography scans. Serum myoglobin and cardiac troponin were tested at admission. The relationship between myoglobin levels and hematoma volume and growth was performed using univariate and multiple logistic regression and linear regression.</div>
<h4 id="absSec_3">
Results</h4>
<div id="sp0020">
High levels of serum myoglobin were associated with larger hematoma volume. In the highest quartile compared with the lowest quartile of myoglobin, the crude and adjusted odds ratios for the incidence of baseline hematoma volume greater than 30 mL were 2.14 (95% confidence interval 1.45-3.15) and 2.78 (95% confidence interval 1.57-5.00), respectively, in logistic regression. In linear regression, the adjusted B for the relationship of myoglobin and hematoma volume and the change of hematoma volume was .02 (95% confidence interval .01-.04, <em>P</em> = .007) and .021 (95% confidence interval .01-.03, <em>P</em> < .001), respectively, whereas high level of troponin T was not associated with large hematoma volume.</div>
<h4 id="absSec_4">
Conclusion</h4>
<div id="sp0025">
Our results first demonstrate that myoglobin is associated with larger hematoma volume and growth after adjusting potential confounding factors.</div>
<br />
<a class="S_C_ddDoi" href="http://dx.doi.org/10.1016/j.jstrokecerebrovasdis.2016.02.005" id="ddDoi" target="doilink">http://dx.doi.org/10.1016/j.jstrokecerebrovasdis.2016.02.005</a><br />
<br />
Ming Liu, MD, PhD, Stroke Clinical Research Unit, Department of Neurology, West China Hospital, Sichuan University, No. 37 Guo Xue Xiang, Chengdu, Sichuan Province 610041, China.Unknownnoreply@blogger.comtag:blogger.com,1999:blog-3041608287215818368.post-61450778012993824542012-10-22T13:04:00.001-07:002012-10-22T13:04:18.793-07:00Prognostic implications of plasma myoglobin levels in patients with chronic kidney disease<br />
Abstract<br />
<br />
<br />
Purpose: Poor cardiovascular outcomes in chronic kidney disease (CKD) patients have prompted nephrologists to look for biomarkers that may improve risk stratification in this population. <br />
<br />
The objective of this study was to evaluate plasma <a href="http://www.leebio.com/myoglobin-mb-human---liquid-P168.html"><span style="color: blue;">myoglobin</span></a> (Mb) levels according to the CKD stage and to determine whether they are associated with overall, cardiovascular (CV) mortality, CV events, and renal outcomes. Methods: Plasma Mb levels were determined in 140 CKD patients at different stage (mean ± SD age: 67 ± 12; males: 61%) who were prospectively monitored for overall and CV mortality, CV events and CKD progression. Twenty-seven healthy subjects served as controls.<br />
<br />
Results: Plasma <a href="http://www.leebio.com/myoglobin-mb-human---liquid-P168.html">Mb</a> levels were higher in CKD patients than in controls and progressively increased as the glomerular filtration rate fell. <a href="http://www.leebio.com/hemoglobin-hb-human-P462.html"><span style="color: blue;">Hemoglobin</span></a> levels, CKD stage, the aortic calcification score and brain natriuretic peptide levels were associated with plasma Mb concentrations. In a multivariate analysis, only CKD stage was associated with Mb levels. During follow up (mean duration: 968 ± 374 days), 44 patients died and 63 had a cardiovascular event. In a crude analysis, plasma Mb >73.8 µg/l predicted overall and cardiovascular <span style="color: black;">mortality</span> and the occurrence of cardiovascular events (p = 0.01, 0.05 and 0.01, respectively). However, this association was lost after adjustment for other prognostic factors for mortality. Plasma Mb was not a significant predictor of the progression of CKD either.<br />
<br />
Conclusions: Plasma <a href="http://www.leebio.com/myoglobin-mb-human---liquid-P168.html"><span style="color: blue;">Myoglobin </span></a>levels were significantly higher in predialysis or dialyzed CKD patients than in healthy controls. However, we could not identify a relevant clinical outcome associated with this elevation. Larger studies are needed to confirm the present results<br />
<br />
French National Institute of Health and Medical Research (INSERM), ERI-12 (EA 4292), Amiens - France and Clinical Research Center-Division of Clinical Pharmacology, Amiens University Hospital and the Jules Verne University of Picardie, Amiens - France
Int J Artif Organs. 2012 Sep 6:0. doi: 10.5301/ijao.5000124.Unknownnoreply@blogger.comtag:blogger.com,1999:blog-3041608287215818368.post-37699792501591239752011-11-13T08:49:00.000-08:002011-11-13T08:51:07.107-08:00Rapid diagnostic protocol for patients with chest painOn the basis of thrombolysis in myocardial infarction (TIMI) score, ECG, and a point-of-care biomarker panel of troponin, creatine kinase MB, and myoglobin, Martin Than and colleagues(1) identified patients with chest pain who were at very low risk of a short-term major adverse cardiac event and who might be suitable for early discharge.<br />
We are a little concerned about missing TIMI score data. The score includes “three or more risk factors for coronary artery disease” and “significant coronary stenosis at previous angiography” (yes=1, no=0). We wonder whether a patient without a regular health check was regarded by Than and colleagues as scoring 0 or 1? This could be an important issue considering the threshold considered (TIMI score ≥1=positive). We know, for instance, that people of low socioeconomic status have a lower access to health care, yet they have more risk factors for coronary heart disease.(2—4) Without a regular check-up, these people might have had a lower TIMI score than they should have.<br />
In conclusion, we think that the accelerated diagnostic protocol should take into account the absence of medical follow-up to consider factors such as health inequalities.<br />
We declare that we have no conflicts of interest.<br />
<br />
References<br />
1 Than M, Cullen L, Reid CM, et al. A 2-h diagnostic protocol to assess patients with chest pain symptoms in the Asia-Pacific region (ASPECT): a prospective observational validation study. Lancet 2011; 377: 1077-1084. Summary | Full Text | PDF(200KB) | CrossRef | PubMed<br />
2 Kaplan GA, Keil JE. Socioeconomic factors and cardiovascular disease: a review of the literature. Circulation 1993; 88: 1973-1998. PubMed<br />
3 Tyroler HA. The influence of socioeconomic factors on cardiovascular disease risk factor development. Prev Med 1999; 29: S36-S40. CrossRef | PubMed<br />
4 Manrique-Garcia E, Sidorchuk A, Hallqvist J, Moradi T. Socioeconomic position and incidence of acute myocardial infarction: a meta-analysis. J Epidemiol Community Health 2011; 65: 301-309. PubMedUnknownnoreply@blogger.comtag:blogger.com,1999:blog-3041608287215818368.post-35331069202201794082011-02-22T14:19:00.001-08:002011-02-22T14:19:33.441-08:00Serum MyoglobinSerum myoglobin is a test that measures the amount of myoglobin in the blood.<br /><br />Myoglobin is a protein in heart and skeletal muscles. When you exercise, your muscles use up any available oxygen. Myoglobin has oxygen attached to it, which provides extra oxygen for the muscle to maintain a high level of activity for a longer period of time.<br /><br />When muscle is damaged, myoglobin is released into the bloodstream. Ultimately, it is removed in the urine.Unknownnoreply@blogger.comtag:blogger.com,1999:blog-3041608287215818368.post-9126879938198928422010-09-15T13:25:00.000-07:002010-09-15T13:26:49.492-07:00Unmasking the Janus face of myoglobin in health and disease.Abstract<br />For more than 100 years, myoglobin has been among the most extensively studied proteins. Since the first comprehensive review on myoglobin function as a dioxygen store by Millikan in 1939 and the discovery of its structure 50 years ago, multiple studies have extended our understanding of its occurrence, properties and functions. Beyond the two major roles, the storage and the facilitation of dioxygen diffusion, recent physiological studies have revealed that myoglobin acts as a potent scavenger of nitric oxide (NO(*)) representing a control system that preserves mitochondrial respiration. In addition, myoglobin may also protect the heart against reactive oxygen species (ROS), and, under hypoxic conditions, deoxygenated myoglobin is able to reduce nitrite to NO(*) leading to a downregulation of the cardiac energy status and to a decreased heart injury after reoxygenation. Thus, by controlling the NO(*) bioavailability via scavenging or formation, myoglobin serves as part of a sensitive dioxygen sensory system. In this review, the physiological relevance of these recent findings are delineated for pathological states where NO(*) and ROS bioavailability are known to be critical determinants for the outcome of the disease, e.g. ischemia/reperfusion injury. Detrimental and beneficial effects of the presence of myoglobin are discussed for various states of tissue oxygen tension within the heart and skeletal muscle. Furthermore, the impact of myoglobin on parasite infection, rhabdomyolysis, hindlimb and liver ischemia, angiogenesis and tumor growth are considered<br /><br />Hendgen-Cotta UB, Flögel U, Kelm M, Rassaf T.<br /><br />Department of Medicine, Division of Cardiology, Pulmonary Diseases and Angiology, University Hospital Düsseldorf, Düsseldorf, Germany.Unknownnoreply@blogger.comtag:blogger.com,1999:blog-3041608287215818368.post-89369393629028811592010-01-28T11:11:00.001-08:002010-01-28T11:11:34.236-08:00mass spectrometric comparison of the interactions of cisplatin and transplatin with myoglobinAbstract<br />Mass spectrometric studies of the interactions of cisplatin and transplatin with myoglobin (Mb) provide information concerning interaction kinetics, Mb adduct identity, and cisplatin and transplatin binding sites on Mb. <br /><br />Although the Mb–cisplatin interaction is faster than the Mb–transplatin interaction, monoadducts and diadducts were formed in both the interactions over 30 h. In order to locate the binding sites of cisplatin and transplatin on Mb, digests of free Mb, Mb–cisplatin and Mb–transplatin adducts were subjected to analysis by Fourier transform mass spectrometry (FT-MS). This analysis revealed that two fragment ions, 1313.275+ and 1316.685+, were obtained only from the Mb–cisplatin and Mb–transplatin adduct digests. <br /><br />Tandem mass spectrometry (MS/MS and MS3) of the 1313.275+ and 1316.685+ ions indicate that these ions arise from [Pt(NH3)]2+ and [Pt(NH3)2]2+, respectively, bound to peptide His97-Gly153. The product-ion spectra of the MS/MS and MS3 analyses of the 1313.275+ ion indicate a common binding site of cisplatin and transplatin on His116-His119 residues. The interactions of cisplatin and transplatin with a dipeptide His-Ser and the three dimensional (3D) structure of native Mb suggest that cisplatin and transplatin coordinate to His116 and His119.<br /><br />Ting Zhaoa and Fred L. King, a, <br /><br />a C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, WV 26506-6045, USAUnknownnoreply@blogger.comtag:blogger.com,1999:blog-3041608287215818368.post-71160076825708680322009-11-24T10:31:00.000-08:002009-11-24T10:35:12.539-08:00Expression and Functional Regulation of Myoglobin in Epithelial Cancers(American Journal of Pathology. 2009;175:201-206.)<br /><br />Myoglobin is a multifunctional heme protein that is thought to be expressed exclusively in myocytes. Its importance in both oxygen transport and free radical scavenging has been extensively characterized. We hypothesized that solid tumors could take advantage of proteins such as myoglobin to cope with hypoxic conditions and to control the metabolism of reactive oxygen and nitrogen species. <br /><br />We therefore sought to establish whether myoglobin might be expressed and functionally regulated in epithelial tumors that are known to face hypoxia and oxidative stress during disease progression. We analyzed the expression of myoglobin in human epithelial cancers at both transcriptional and protein levels; moreover, we investigated the expression levels of myoglobin in cancer cell lines subjected to different conditions, including hypoxia, oxidative stress, and mitogenic stimuli. We provide evidence that human epithelial tumors, including breast, lung, ovary, and colon carcinomas, express high levels of myoglobin from the earliest stages of disease development. <br /><br />In human cancer cells, myoglobin is induced by a variety of signals associated with tumor progression, including mitogenic stimuli, oxidative stress, and hypoxia. This study provides evidence that myoglobin, previously thought to be restricted to myocytes, is expressed at high levels by human carcinoma cells. We suggest that myoglobin expression is part of a cellular program aimed at coping with changed metabolic and environmental conditions associated with neoplastic growth. <br /><br /><br />Expression and Functional Regulation of Myoglobin in Epithelial Cancers<br />Simona Emilia Flonta*, Sabrina Arena*, Alberto Pisacane, Paolo Michieli and Alberto Bardelli* From the Laboratory of Molecular Genetics,* the Unit of Pathology, and the Division of Molecular Oncology, Institute for Cancer Research and Treatment, University of Turin Medical School, Turin; and the FIRC Institute of Molecular Oncology, Milan, ItalyUnknownnoreply@blogger.comtag:blogger.com,1999:blog-3041608287215818368.post-5730015186268041492009-08-20T09:18:00.000-07:002009-08-20T09:19:16.483-07:00Myoglobin causes oxidative stress, increase of NO production and dysfunction of kidney's mitochondriaPlotnikov EY, Chupyrkina AA, Pevzner IB, Isaev NK, Zorov DB.<br />A.N.Belozersky Institute of Physico-Chemical Biology, and Institute of Mitoingeneering, Moscow State University, Moscow 119991, Russia.<br /><br />Rhabdomyolysis or crush syndrome is a pathology caused by muscle injury resulting in acute renal failure. The latest data give strong evidence that this syndrome caused by accumulation of muscle breakdown products in the blood stream is associated with oxidative stress with primary role of mitochondria. In order to evaluate the significance of oxidative stress under rhabdomyolysis we explored the direct effect of myoglobin on renal tubules and isolated kidney mitochondria while measuring mitochondrial respiratory control, production of reactive oxygen and nitrogen species and lipid peroxidation. In parallel, we evaluated mitochondrial damage under myoglobinurea in vivo. An increase of lipid peroxidation products in kidney mitochondria and release of cytochrome c was detected on the first day of myoglobinuria. In mitochondria incubated with myoglobin we detected respiratory control drop, uncoupling of oxidative phosphorylation, an increase of lipid peroxidation products and stimulated NO synthesis. Mitochondrial pore inhibitor, cyclosporine A, mitochondria-targeted antioxidant (SkQ1) and deferoxamine (Fe-chelator and ferryl-myoglobin reducer) abrogated these events. Similar effects (oxidative stress and mitochondrial dysfunction) were revealed when myoglobin was added to isolated renal tubules. Thus, rhabdomyolysis can be considered as oxidative stress-mediated pathology with mitochondria to be the primary target and possibly the source of reactive oxygen and nitrogen species. We speculate that rhabdomyolysis-induced kidney damage involves direct interaction of myoglobin with mitochondria possibly resulting in iron ions release from myoglobin's heme, which promotes the peroxidation of mitochondrial membranes. Usage of mitochondrial permeability transition blockers, Fe-chelators or mitochondria-targeted antioxidants, may bring salvage from this pathologyUnknownnoreply@blogger.comtag:blogger.com,1999:blog-3041608287215818368.post-69723245540573365922009-06-22T09:09:00.000-07:002009-06-22T09:16:12.996-07:00Serum myoglobin and renal morbidity and mortalityOBJECTIVES: The intractability of renal dysfunction following thoracic and thoraco-abdominal aortic repair leads us to believe that the accepted mechanisms of renal injury - ischaemia and embolism - are incompletely explanatory. We studied postoperative myoglobinaemia and renal dysfunction following aortic surgery. <br /><br />METHODS: Between September 2006 and February 2008, we studied serum myoglobin in 109 patients requiring thoracic/thoraco-abdominal repair for three postoperative days. Forty-two of the 109 (38%) patients were female. The median age was 67 years (range 23-84 years). As we have focussed more attention on renal function, our independent renal consultants have dialysed more aggressively. We divided dialysis into: (1) creatinine indication, (2) non-creatinine indication and (3) no dialysis. <br /><br />RESULTS: Thirteen of the 109 (12%) patients met creatinine indication for dialysis (>4 mg dl(-1)) and an additional 28 (26%) were dialysed for other reasons. Overall mortality was 12 out of 109 (11%) cases: 11 out of 41 (27%) in dialysed patients and one out of 68 (1.5%) in non-dialysed patients. Mortality did not differ between the indications for dialysis. Predictors of mortality were baseline glomerular filtration rate (GFR), postoperative myoglobin and dialysis. The only predictor of dialysis was postoperative myoglobin. <br /><br />CONCLUSION: A strong relationship between postoperative serum myoglobin and renal failure suggests a rhabdomyolysis-like contributing aetiology following thoraco-abdominal aortic repair. We postulate a novel mechanism of renal injury for which mitigation strategies should be developed.<br /><br />Miller CC 3rd, Villa MA, Sutton J, Lau D, Keyhani K, Estrera AL, Azizzadeh A, Coogan SM, Safi HJ.<br />Department of Cardiothoracic and Vascular Surgery, University of Texas Medical School at Houston, Memorial Hermann Heart and Vascular Institute, Houston, TX 77030,Unknownnoreply@blogger.comtag:blogger.com,1999:blog-3041608287215818368.post-49822149704908444882009-05-19T18:29:00.000-07:002009-05-19T18:31:01.696-07:00Roles of the creatine kinase system and myoglobin in maintaining energetic state in the working heart.Wu F, Beard DA.<br />Biotechnology and Bioengineering Center, Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, USA. <br /><br />BACKGROUND: The heart is capable of maintaining contractile function despite a transient decrease in blood flow and increase in cardiac ATP demand during systole. This study analyzes a previously developed model of cardiac energetics and oxygen transport to understand the roles of the creatine kinase system and myoglobin in maintaining the ATP hydrolysis potential during beat-to-beat transient changes in blood flow and ATP hydrolysis rate. <br /><br />RESULTS: The theoretical investigation demonstrates that elimination of myoglobin only slightly increases the predicted range of oscillation of cardiac oxygenation level during beat-to-beat transients in blood flow and ATP utilization. In silico elimination of myoglobin has almost no impact on the cytoplasmic ATP hydrolysis potential (DeltaGATPase). In contrast, disabling the creatine kinase system results in considerable oscillations of cytoplasmic ADP and ATP levels and seriously deteriorates the stability of DeltaGATPase in the beating heart. <br /><br />CONCLUSION: The CK system stabilizes DeltaGATPase by both buffering ATP and ADP concentrations and enhancing the feedback signal of inorganic phosphate in regulating mitochondrial oxidative phosphorylation.Unknownnoreply@blogger.comtag:blogger.com,1999:blog-3041608287215818368.post-58260322469524990732008-07-17T14:18:00.000-07:002008-07-17T14:21:12.859-07:00A potentiometric protein sensor built with surface molecular imprinting methodSurface molecular imprinting, as compared to molecular imprinted bulk polymers, has the advantages of higher re-occupation percentage of the reception sites, fast response, integration of sensing element and transducer, etc. In this study, a potentiometric protein sensor was developed based on the surface molecular imprinting technique. Using the self-assembled monolayers of alkanethiol with hydroxyl terminal groups as the matrix material, and target protein molecules as the template, the sensing layer was created on the surface of the gold-coated silicon chip-an electrochemical transducer. Potentiometric measurement demonstrated that the sensor could selectively detect <a href="http://www.leebio.com/products.php?search=myoglobin">myoglobin</a> or <a href="http://www.leebio.com/products.php?search=hemoglobin">hemoglobin</a> molecules, either with or without the presence of other protein molecules in the same solution.<br /><br /><a href="http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6TFC-4SB7TT9-2&_user=10&_coverDate=09%2F15%2F2008&_alid=768066369&_rdoc=1&_fmt=high&_orig=search&_cdi=5223&_sort=d&_docanchor=&view=c&_ct=3101&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=8352080e0772dc5cc28dfbd2f36c585d">ARTICLE</a>Unknownnoreply@blogger.comtag:blogger.com,1999:blog-3041608287215818368.post-88761758919228244372008-07-14T13:13:00.000-07:002008-07-17T14:36:59.565-07:00Biochemical impact of a soccer match — analysis of oxidative stress and muscle damage markers throughout recovery<strong>Background</strong><br />Exercise is a prone condition to enhanced oxidative stress and damage and the specific activity pattern of a soccer match may favour additional pro-oxidant redox alterations. To date, no studies have reported the impact of a soccer match on oxidative stress and muscle damage markers.<br /><br /><strong>Aim</strong><br />To analyse the effect of a competitive soccer match on plasma levels of oxidative stress and muscle damage markers, and to relate these findings with lower limb functional data.<br /><br /><strong>Methods</strong><br />Blood samples, leg muscle strength, sprint ability and delayed-onset muscle soreness (DOMS) were obtained in 16 soccer players before, at 30 min, 24, 48 and 72 h after a soccer match. Plasma <a href="http://www.leebio.com/creatine-kinase-total-human-P57.html">creatine kinase (CK)</a>, <a href="http://www.leebio.com/myoglobin-mb-human-P168.html">myoglobin (Mb)</a>, <a href="http://en.wikipedia.org/wiki/Malondialdehyde">malondialdehyde (MDA)</a>, <a href="http://medical-dictionary.thefreedictionary.com/Sulfhydryl+group">sulfhydryl (–SH) groups</a>, <a href="http://www.kingjamesomegatech-lab.com/total.htm">total antioxidant status (TAS)</a>, <a href="http://en.wikipedia.org/wiki/Uric_acid">uric acid (UA)</a> and <a href="http://www.leebio.com/products.php?search=leukocyte">blood leukocyte</a> counts were determined.<br /><br /><strong>Results</strong><br />A soccer match elevated plasma Mb following 30 min and <a href="http://www.leebio.com/creatine-kinase-total-human-P57.html">creatine kinase (CK)</a> levels throughout the 72 h-recovery period. MDA increased throughout the recovery period and –SH decreased until 48 h post-match. TAS increased at 30 min and UA increased throughout the 72 h recovery. Blood neutrophils increased at 30 min whereas lymphocytes decreased and returned to baseline from 24 to 72 h. DOMS was higher than baseline until 72 h. Lower limb strength and sprint ability were lower than baseline until 72 h recovery.<br /><br /><strong>Conclusion</strong><br />The present data suggest that a soccer match increases the levels of oxidative stress and muscle damage throughout the 72 h-recovery period. The extent to which the redox alterations are associated with the recovery of muscle function should be further analysed.<br /><br /><a href="http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6TDD-4SBSDJ5-3&_user=10&_coverDate=07%2F31%2F2008&_alid=766607413&_rdoc=12&_fmt=high&_orig=search&_cdi=5196&_sort=d&_docanchor=&view=c&_ct=3099&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=bb8374c25c6c3efc4decf79fd578d22c">ARTICLE</a>Unknownnoreply@blogger.comtag:blogger.com,1999:blog-3041608287215818368.post-70755698357859853322008-07-10T12:42:00.000-07:002008-07-17T14:34:38.392-07:00Toward Quantitative Simulations of Carbon Monoxide Escape Pathways in MyoglobinStraightforward molecular dynamics trajectories have been computed to explore the diffusion of carbon monoxide through <a href="http://www.leebio.com/myoglobin-mb-human-P168.html">myoglobin</a>. The classical equations of motion were integrated for 2 ns and the resulting pathways analyzed. Two types of runs were examined. Type i: <a href="http://www.leebio.com/myoglobin-mb-human-P168.html">myoglobin</a> and a ligand embedded in a periodic box with 9996 water molecules; the water molecules are rigid but the bonds of the protein are flexible. Type ii:<a href="http://www.leebio.com/myoglobin-mb-human-P168.html">myoglobin</a> with a solvation shell (153 water molecules) in which all bond lengths are fixed. In trajectories of type i, the diffusing ligand visits a significant part of the protein matrix and was not constrained to the proximity of the heme pocket before escaping. The maximum time of the trajectories was 2 ns. It was shorter if the ligand escaped earlier. Two ligands (from a total of 88) escape to the solvent from nonclassical gates (non-E-helix gates). In trajectories of type ii, the overall fluctuations of the protein are smaller and the ligand explores significantly smaller internal space. The escape rate from type ii trajectories (11 of 400) is comparable to type i and is not dramatically different from experiment (1 of 100). Interestingly, the two simulations with comparable rates sampled different pathways. In trajectories of type ii, we observe escapes from the classical gate (His 64) and from the Xe4 cavity. Further studies (that are underway) are required to define the escape pathways and the overall rate.Unknownnoreply@blogger.comtag:blogger.com,1999:blog-3041608287215818368.post-2135989624489742852008-07-08T13:56:00.000-07:002008-07-17T14:33:39.252-07:00What is Myoglobin?<a href="http://www.leebio.com/myoglobin-P168.html">Myoglobin</a> is a cytoplasmic hemoprotein that is restricted to cardiomyocytes and oxidative skeletal muscle fibers. <a href="http://www.leebio.com/myoglobin-P168.html">Myoglobin</a> is a well-characterized protein and numerous studies have established that it has an essential role in facilitated oxygen transport in striated muscles. Recent strategies, using gene disruption technologies, have produced mice that lack myoglobin. These myoglobin deficient mice have a binary phenotype and a subpopulation of these mutant mice is viable and fertile. Characterization of the viable myoglobin null mice has uncovered a number of molecular and cellular adaptive mechanisms that function to promote oxygen delivery in the mutant striated muscle cell. Moreover, cellular and physiological studies, using the myoglobin deficient mouse model, support the conclusion that the functions of myoglobin include: facilitated oxygen transport, the storage of oxygen and a scavenger of nitric oxide or reactive oxygen species. Collectively, the use of genetic mouse models will further enhance our understanding of myoglobin function in normal and pathological muscle lineages.Unknownnoreply@blogger.comtag:blogger.com,1999:blog-3041608287215818368.post-52016112033336007182008-07-08T13:52:00.000-07:002008-07-17T14:33:04.747-07:00Third generation biosensor based on myoglobin-TiO2/MWCNTs modified glassy carbon electrode<a href="http://ruby.colorado.edu/~smyth/min/tio2.html">TiO2 nanoparticles</a> were homogeneously coated on multi-walled carbon nanotubes by hydrothermal deposition, this nanocomposite may be a promising material for <a href="http://www.leebio.com/myoglobin-P168.html">myoglobin</a> immobilization in view of its high biocompatibility and large surface. The glassy carbon electrode modified with Mb-TiO2/MWCNTs films exhibited a pair of well defined, stable and nearly reversible cycle voltammetric peaks. The electron transfer between Mb and electrode surface, Ks of 3.08 s−1, was greatly facilitated in the TiO2/MWCNTs film. The electrocatalytic reductions of hydrogen peroxide were studied, the apparent Michaelis–Menten constant is calculated to be 83.10 μmol/L, which shows a large catalytic activity of Mb in the TiO2/MWCNTs film to H2O2.<br /><br /><br /><a href="http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B8G3X-4SW8B2W-3&_user=10&_coverDate=08%2F31%2F2008&_alid=764284904&_rdoc=4&_fmt=high&_orig=search&_cdi=41806&_docanchor=&view=c&_ct=3095&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=64feb50ffb41e1e43949c80a371145e1">ARTICLE</a>Unknownnoreply@blogger.comtag:blogger.com,1999:blog-3041608287215818368.post-52876238997328392542008-07-08T13:44:00.000-07:002008-07-17T14:32:13.778-07:00A potentiometric protein sensor built with surface molecular imprinting methodSurface molecular imprinting, as compared to molecular imprinted bulk polymers, has the advantages of higher re-occupation percentage of the reception sites, fast response, integration of sensing element and transducer, etc. In this study, a potentiometric protein sensor was developed based on the surface molecular imprinting technique. Using the self-assembled monolayers of alkanethiol with hydroxyl terminal groups as the matrix material, and target protein molecules as the template, the sensing layer was created on the surface of the gold-coated silicon chip-an electrochemical transducer. Potentiometric measurement demonstrated that the sensor could selectively detect <a href="http://www.leebio.com/myoglobin-P168.html">myoglobin</a> or <a href="http://www.leebio.com/hemoglobin-human-P462.html">hemoglobin</a> molecules, either with or without the presence of other protein molecules in the same solution.<br /><br /><a href="http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6TFC-4SB7TT9-2&_user=10&_coverDate=09%2F15%2F2008&_alid=764284904&_rdoc=1&_fmt=high&_orig=search&_cdi=5223&_docanchor=&view=c&_ct=3095&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=67ed79efc935946e1f5d71286a95a8d8">ARTICLE</a>Unknownnoreply@blogger.com