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1.
Gerodontology ; 40(1): 142-144, 2023 Mar.
Article in English | MEDLINE | ID: mdl-36468370

ABSTRACT

Oral liposarcomas are uncommon diseases, the most predominant histopathological subtype being atypical lipomatous tumour/well-differentiated liposarcoma. In regard to its clinical aspects in the oral cavity, it is challenging to confirm a diagnosis and develop a treatment plan. In this case report, we present a rare case of atypical lipomatous tumour/well-differentiated liposarcoma in the right cheek of a 77-year-old male patient. Conservative surgery was performed considering the histopathological subtype of the neoplasm. Knowledge of the clinical and histopathological characteristics of this rare disease is essential to maintaining function and aesthetics through conservative treatment in older patients.


Subject(s)
Liposarcoma , Mouth Mucosa , Male , Humans , Aged , Mouth Mucosa/pathology , Liposarcoma/diagnosis , Liposarcoma/pathology , Liposarcoma/surgery , Diagnosis, Differential , Mouth
2.
Neuroimage Clin ; 30: 102610, 2021.
Article in English | MEDLINE | ID: mdl-33752076

ABSTRACT

PURPOSE: The purpose of this study was to investigate UHb-rDWI signal in white matter tracts of the cervical spinal cord (CSC) and compare quantitative values between healthy control WM with both MS NAWM and MS WM lesions. METHODS: UHb-rDWI experiments were performed on (a) 7 MS patients with recently active or chronic lesions in CSC and on (b) 7 healthy control of similar age range and gender distribution to MS subjects. All MRI data were acquired using clinical 3T MRI system. Axial high-b diffusion images were acquired using 2D single-shot DW stimulated EPI with reduced FOV and a CSC-dedicated 8 channel array coil. High-b diffusion coefficient DH was estimated by fitting the signal-b curve to a double or single-exponential function. RESULTS: The high-b diffusivity DH values were measured as (0.767 ± 0.297) × 10-3 mm2/s in the posterior column lesions, averaged over 6 MS patients, and 0.587 × 10-3 mm2/s in the corticospinal tract for another patient. The averaged DH values of the 7 healthy volunteers from the posterior and lateral column were (0.0312 ± 0.0306) × 10-3 and (0.0505 ± 0.0205) × 10-3 mm2/s, respectively. UHb-rDWI signal-b curves of the MS patients revealed to noticeably behave differently to that of the healthy controls. The patient signal-b curves decayed with greater high-b decay constants to reach lower signal intensities relative to signal-b curves of the healthy controls. CONCLUSION: UHb-DWI of the CSC reveals a marked difference in signal-b-curves and DH values in MS lesions compared to NAWM and healthy control WM. Based on physical principles, we interpret these altered observations of quantitative diffusion values to be indicative of demyelination. Further studies in animal models will be required to fully interpret UHb-DWI quantitative diffusion values during demyelination and remyelination.


Subject(s)
Cervical Cord , White Matter , Animals , Cervical Cord/diagnostic imaging , Diffusion Magnetic Resonance Imaging , Humans , Spinal Cord , White Matter/diagnostic imaging
3.
Diagnostics (Basel) ; 12(1)2021 Dec 23.
Article in English | MEDLINE | ID: mdl-35054187

ABSTRACT

The aim of this study was to compare the effect of using depth of invasion (DOI) versus tumor thickness (TT) as a prognostic factor for early-stage oral squamous cell carcinoma (OSCC). A total of 57 patients with early-stage OSCC treated surgically from 2009 to 2014 at our institution were reviewed retrospectively. Histopathological measurement of DOI and TT was performed. The validation of DOI and TT as prognostic factors was conducted using a Kaplan-Meier survival analysis. TT had no association with disease-specific survival (DSS) or progression-free survival (PFS) in this cohort; however, increased DOI was significantly associated with decreased DSS but not correlated to decreased PFS. The T category of the 7th edition of AJCC was statistically associated with both DSS and PFS; however, the T category of the 8th edition of the AJCC was only associated with DSS. In this study group, TT could not be used as a prognostic factor, and DOI was not by itself sufficient to predict prognosis for early-stage OSCC. The T category in AJCC 8th Edition cannot be considered the sole prognostic factor for early OSCC, so additional prognostic factors may need to be considered.

4.
Int J Mol Sci ; 21(9)2020 Apr 25.
Article in English | MEDLINE | ID: mdl-32344926

ABSTRACT

AIMS: Coxsackievirus B3 (CVB3) is known to be an important cause of myocarditis and dilated cardiomyopathy. Enterovirus-2C (E2C) is a viral RNA helicase. It inhibits host protein synthesis. Based on these facts, we hypothesize that the inhibition of 2C may suppress virus replication and prevent enterovirus-mediated cardiomyopathy. METHODS AND RESULTS: We generated a chemically modified enterovirus-2C inhibitor (E2CI). From the in vitro assay, E2CI was showed strong antiviral effects. For in vivo testing, mice were treated with E2CI intraperitoneally injected daily for three consecutive days at a dose of 8mg/kg per day, after CVB3 post-infection (p.i) (CVB3 + E2CI, n = 33). For the infected controls (CVB3 only, n = 35), mice were injected with PBS (phosphate buffered saline) in a DBA/2 strain to establish chronic myocarditis. The four-week survival rate of E2CI-treated mice was significantly higher than that of controls (92% vs. 71%; p < 0.05). Virus titers and myocardial damage were significantly reduced in the E2CI treated group. In addition, echocardiography indicated that E2CI administration dramatically maintained mouse heart function compared to control at day 28 p.i chronic stage (LVIDD, 3.1 ± 0.08 vs. 3.9 ± 0.09, p < 0.01; LVDS, 2.0 ± 0.07 vs. 2.5 ± 0.07, p < 0.001; FS, 34.8 ± 1.6% vs. 28.5 ± 1.5%; EF, 67. 9 ± 2.9% vs. 54.7 ± 4.7%, p < 0.05; CVB3 + E2CI, n = 6 vs. CVB3, n = 4). Moreover, E2CI is effectively worked in human iPS (induced pluripotent stem cell) derived cardiomyocytes. CONCLUSION: Enterovirus-2C inhibitor (E2CI) was significantly reduced viral replication, chronic myocardium damage, and CVB3-induced mortality in DBA/2 mice. These results suggested that E2CI is a novel therapeutic agent for the treatment of enterovirus-mediated diseases.


Subject(s)
Antiviral Agents/pharmacology , Coxsackievirus Infections/drug therapy , Enterovirus B, Human/enzymology , Induced Pluripotent Stem Cells/drug effects , Myocarditis/prevention & control , Myocytes, Cardiac/drug effects , RNA Helicases/antagonists & inhibitors , Viral Proteins/antagonists & inhibitors , Animals , Antiviral Agents/chemical synthesis , Antiviral Agents/therapeutic use , Cardiomyopathy, Dilated/etiology , Cardiomyopathy, Dilated/prevention & control , Chronic Disease , Coxsackievirus Infections/complications , Enterovirus B, Human/drug effects , Enterovirus B, Human/physiology , HeLa Cells , Humans , Induced Pluripotent Stem Cells/virology , Luciferases, Renilla/analysis , Male , Mice , Mice, Inbred DBA , Myocarditis/etiology , Myocarditis/virology , Myocytes, Cardiac/pathology , Myocytes, Cardiac/virology , Oxadiazoles/pharmacology , Oxadiazoles/therapeutic use , Oxazoles/pharmacology , Oxazoles/therapeutic use , Recombinant Fusion Proteins/metabolism , Ventricular Dysfunction, Left/etiology , Ventricular Dysfunction, Left/prevention & control , Virus Replication/drug effects
5.
Bioorg Med Chem ; 27(18): 4110-4123, 2019 09 15.
Article in English | MEDLINE | ID: mdl-31378598

ABSTRACT

The sulfonamidophenylethylamide analogues were explored for finding novel and potent cardiac myosin activators. Among them, N-(4-(N,N-dimethylsulfamoyl)phenethyl-N-methyl-5-phenylpentanamide (13, CMA at 10 µM = 48.5%; FS = 26.21%; EF = 15.28%) and its isomer, 4-(4-(N,N-dimethylsulfamoyl)phenyl-N-methyl-N-(3-phenylpropyl)butanamide (27, CMA at 10 µM = 55.0%; FS = 24.69%; EF = 14.08%) proved to be efficient cardiac myosin activators both in in vitro and in vivo studies. Compounds 13 (88.2 + 3.1% at 5 µM) and 27 (46.5 + 2.8% at 5 µM) showed positive inotropic effect in isolated rat ventricular myocytes. The potent compounds 13 and 27 were highly selective for cardiac myosin over skeletal and smooth muscle myosin, and therefore these potent and selective amide derivatives could be considered a new class of cardiac myosin activators for the treatment of systolic heart failure.


Subject(s)
Amides/therapeutic use , Cardiac Myosins/drug effects , Amides/pharmacology , Humans , Structure-Activity Relationship
6.
J Clin Med ; 8(3)2019 Mar 15.
Article in English | MEDLINE | ID: mdl-30875971

ABSTRACT

An angiotensin receptor blocker (ARB) mitigates cardiac remodeling after myocardial infarction (MI). Here, we investigated the effect of fimasartan, a new ARB, on cardiac remodeling after MI. Sprague⁻Dawley rats were assigned into 3 groups: surgery only (sham group, n = 7), MI without (MI-only group, n = 13), and MI with fimasartan treatment (MI + Fima group, n = 16). MI was induced by the permanent ligation of the left anterior descending artery. Treatment with fimasartan (10 mg/kg) was initiated 24 h after MI and continued for 7 weeks. Rats in the MI + Fima group had a higher mean ejection fraction (66.3 ± 12.5% vs. 51.3 ± 14.8%, P = 0.002) and lower left ventricular end-diastolic diameter (9.14 ± 1.11 mm vs. 9.91 ± 1.43 mm, P = 0.045) than those in the MI-only group at 7 weeks after MI. The infarct size was lower in the MI + Fima than in the MI group (P < 0.05). A microarray analysis revealed that the expression of genes related to the lipid metabolism and mitochondrial membrane ion transporters were upregulated, and those involved in fibrosis and inflammation were downregulated by fimasartan. Fimasartan attenuates cardiac remodeling and dysfunction in rats after MI and may prevent the progression to heart failure after MI.

7.
Obstet Gynecol Sci ; 61(2): 247-252, 2018 Mar.
Article in English | MEDLINE | ID: mdl-29564316

ABSTRACT

OBJECTIVE: To compare human chorionic gonadotropin (HCG)-administered natural cycle with spontaneous ovulatory cycle in patients undergoing frozen-thawed embryo transfer (FTET) in natural cycles. METHODS: In this retrospective cohort study, we analyzed the clinical outcome of a total of 166 consecutive FTET cycles that were performed in either natural cycle controlled by HCG for ovulation triggering (HCG group, n=110) or natural cycle with spontaneous ovulation (control group, n=56) in 166 infertile patients between January 2009 and November 2013. RESULTS: There were no differences in patients' characteristics between the 2 groups. The numbers of oocytes retrieved, mature oocytes, fertilized oocytes, grade I or II embryos and frozen embryos in the previous in vitro fertilization (IVF) cycle in which embryos were frozen were comparable between the HCG and control groups. Significant differences were not also observed between the 2 groups in clinical pregnancy rate (CPR), embryo implantation rate, miscarriage rate, live birth rate and multiple CPR. However, the number of hospital visits for follicular monitoring was significantly fewer in the HCG group than in the control group (P<0.001). CONCLUSION: Our results demonstrated that HCG administration for ovulation triggering in natural cycle reduces the number of hospital visits for follicular monitoring without any detrimental effect on FTET outcome when compared with spontaneous ovulatory cycles in infertile patients undergoing FTET in natural ovulatory cycles.

8.
Eur J Med Chem ; 143: 1869-1887, 2018 Jan 01.
Article in English | MEDLINE | ID: mdl-29224951

ABSTRACT

To optimize the lead urea scaffold 1 and 2 as selective cardiac myosin ATPase activator, a series of urea derivatives have been synthesized to explore its structure activity relationship. Among them N,N-dimethyl-4-(2-(3-(3-phenylpropyl)ureido)ethyl)benzenesulfonamide (13, CMA = 91.6%, FS = 17.62%; EF = 11.55%), N,N-dimethyl-4-(2-(1-methyl-3-(3-phenylpropyl)ureido)ethyl)benzene sulfonamide (40, CMA = 52.3%, FS = 38.96%; EF = 24.19%) and N,N-dimethyl-4-(2-(3-methyl-3-(3-phenylpropyl)ureido)ethyl)benzenesulfonamide (41, CMA = 47.6%, FS = 23.19%; EF = 15.47%) proved to be efficient to activate the cardiac myosin in vitro and in vivo. Further the % change in ventricular cell contractility at 5 µM of 13 (47.9 ± 3.2), 40 (45.5 ± 2.4) and 41 (63.5 ± 2.2) showed positive inotropic effect in isolated rat ventricular myocytes. The potent compounds 13, 40, 41 were highly selective for cardiac myosin over skeletal and smooth muscle myosin, thus proving them these new urea derivatives is a novel scaffold for discovery of cardiac myosin activators for the treatment of systolic heart failure.


Subject(s)
Cardiac Myosins/drug effects , Drug Design , Urea/pharmacology , Animals , Cardiac Myosins/metabolism , Dose-Response Relationship, Drug , Male , Molecular Structure , Rats , Rats, Sprague-Dawley , Structure-Activity Relationship , Urea/analogs & derivatives , Urea/chemistry
9.
Toxins (Basel) ; 9(9)2017 09 15.
Article in English | MEDLINE | ID: mdl-28914784

ABSTRACT

Neuropathic pain in a chronic post-ischaemic pain (CPIP) model mimics the symptoms of complex regional pain syndrome type I (CRPS I). The administration of bee venom (BV) has been utilized in Eastern medicine to treat chronic inflammatory diseases accompanying pain. However, the analgesic effect of BV in a CPIP model remains unknown. The application of a tight-fitting O-ring around the left ankle for a period of 3 h generated CPIP in C57/Bl6 male adult mice. BV (1 mg/kg ; 1, 2, and 3 times) was administered into the SC layer of the hind paw, and the antiallodynic effects were investigated using the von Frey test and by measuring the expression of neurokinin type 1 (NK-1) receptors in dorsal root ganglia (DRG). The administration of BV dose-dependently reduced the pain withdrawal threshold to mechanical stimuli compared with the pre-administration value and with that of the control group. After the development of the CPIP model, the expression of NK-1 receptors in DRG increased and then decreased following the administration of BV. SC administration of BV results in the attenuation of allodynia in a mouse model of CPIP. The antiallodynic effect was objectively proven through a reduction in the increased expression of NK-1 receptors in DRG.


Subject(s)
Bee Venoms/pharmacology , Hyperalgesia/therapy , Reflex Sympathetic Dystrophy/therapy , Analgesics/pharmacology , Analgesics/therapeutic use , Animals , Bee Venoms/therapeutic use , Dose-Response Relationship, Drug , Ganglia, Spinal/metabolism , Mice , Receptors, Neurokinin-1/biosynthesis , Reflex Sympathetic Dystrophy/physiopathology
10.
Eur J Med Chem ; 134: 379-391, 2017 Jul 07.
Article in English | MEDLINE | ID: mdl-28432943

ABSTRACT

A series of flexible urea derivatives have been synthesized and demonstrated as selective cardiac myosin ATPase activator. Among them 1-phenethyl-3-(3-phenylpropyl)urea (1, cardiac myosin ATPase activation at 10 µM = 51.1%; FS = 18.90; EF = 12.15) and 1-benzyl-3-(3-phenylpropyl)urea (9, cardiac myosin ATPase activation = 53.3%; FS = 30.04; EF = 18.27) showed significant activity in vitro and in vivo. The change of phenyl ring with tetrahydropyran-4-yl moiety viz., 1-(3-phenylpropyl)-3-((tetrahydro-2H-pyran-4-yl)methyl)urea (14, cardiac myosin ATPase activation = 81.4%; FS = 20.50; EF = 13.10), and morpholine moiety viz., 1-(2-morpholinoethyl)-3-(3-phenylpropyl)urea (21, cardiac myosin ATPase activation = 44.0%; FS = 24.79; EF = 15.65), proved to be efficient to activate the cardiac myosin. The potent compounds 1, 9, 14 and 21 were found to be selective for cardiac myosin over skeletal and smooth myosins. Thus, these urea derivatives are potent scaffold to develop as a newer cardiac myosin activator for the treatment of systolic heart failure.


Subject(s)
Cardiac Myosins/metabolism , Cardiotonic Agents/chemistry , Cardiotonic Agents/therapeutic use , Heart Failure, Systolic/drug therapy , Heart/drug effects , Urea/analogs & derivatives , Urea/therapeutic use , Animals , Drug Design , Echocardiography , Heart/diagnostic imaging , Heart Failure, Systolic/diagnostic imaging , Heart Failure, Systolic/metabolism , Humans , Male , Rats, Sprague-Dawley
11.
J Korean Med Sci ; 30(5): 559-68, 2015 May.
Article in English | MEDLINE | ID: mdl-25931786

ABSTRACT

Angiotensin receptor blockers (ARBs) have organ-protective effects in heart failure and may be also effective in doxorubicin-induced cardiomyopathy (DOX-CMP); however, the efficacy of ARBs on the prevention of DOX-CMP have not been investigated. We performed a preclinical experiment to evaluate the preventive effect of a novel ARB, fimasartan, in DOX-CMP. All animals underwent echocardiography and were randomly assigned into three groups: treated daily with vehicle (DOX-only group, n=22), 5 mg/kg of fimasartan (Low-fima group, n=22), and 10 mg/kg of fimasartan (High-fima group, n=19). DOX was injected once a week for six weeks. Echocardiography and hemodynamic assessment was performed at the 8th week using a miniaturized conductance catheter. Survival rate of the High-fima group was greater (100%) than that of the Low-fima (75%) and DOX-only groups (50%). Echocardiography showed preserved left ventricular (LV) ejection fraction in the High-fima group, but not in the DOX-only group (P=0.002). LV dimensions increased in the DOX-only group; however, remodeling was attenuated in the Low-fima and High-fima groups. Hemodynamic assessment showed higher dP/dt in the High-fima group compared with the DOX-only group. A novel ARB, fimasartan, may prevent DOX-CMP and improve survival rate in a dose-dependent manner in a rat model of DOX-CMP and could be a treatment option for the prevention of DOX-CMP.


Subject(s)
Angiotensin Receptor Antagonists/therapeutic use , Biphenyl Compounds/therapeutic use , Cardiomyopathies/prevention & control , Doxorubicin/toxicity , Pyrimidines/therapeutic use , Receptor, Angiotensin, Type 1/metabolism , Tetrazoles/therapeutic use , Animals , Cardiomyopathies/chemically induced , Cardiomyopathies/mortality , Echocardiography , Hemodynamics , Rats , Rats, Sprague-Dawley , Receptor, Angiotensin, Type 1/chemistry , Survival Rate , Ventricular Function, Left/physiology
12.
Virus Res ; 199: 1-8, 2015 Mar 02.
Article in English | MEDLINE | ID: mdl-25485472

ABSTRACT

BACKGROUND: Coxsackievirus B3 (CVB3) is a common cause of myocarditis and dilated cardiomyopathy. CVB3 3C protease (3CP) cleaves the viral polyprotein during replication. We tested whether a water soluble 3CP inhibitor (3CPI) had antiviral effects in a chronic myocarditis model. METHODS: Chronic myocarditis was established using DBA/2 strain mice. Starting on post-infection (p.i) day 3, CVB3-infected mice (n=41) were treated with 3CPI by daily intraperitoneal (i.p.) injection at a concentration of 50 µM (1.7 mg/kg/day) per day for 3 consecutive days. Additional mice (n=49) were injected with PBS as a control. RESULTS: The 5-week survival rate was significantly higher with 3CPI treatment (82.3% versus 47.9%; P<0.05). Organ virus titers at day 3 and 7 and myocardial damage were significantly lower in 3CPI-treated mice. Echocardiography at day 31 indicated strong protection of heart function by 3CPI (FS, 51.2±1.5 versus 26.1±1.5%; P<0.001). Hemodynamic measurements indicated that 3CPI treatment markedly reduced CVB3-induced LV dysfunction on day 31 (dP/dTmax, 5302±352 versus 4103±408 mmHg/s, P<0.05; dP/dTmin, -3798±212 versus -2814±206 mmHg/s, P<0.01). CONCLUSIONS: Water soluble 3CPI was delivered through i.p. injection after CVB3 infection. This agent preserved heart function and decreased organ viral titers and myocardial damage. Soluble 3CPI may be beneficial in the treatment of cardiomyopathy associated with enterovirus infection.


Subject(s)
Antiviral Agents/administration & dosage , Cardiomyopathies/prevention & control , Coxsackievirus Infections/prevention & control , Enterovirus B, Human/enzymology , Protease Inhibitors/administration & dosage , Viral Proteins/antagonists & inhibitors , 3C Viral Proteases , Animals , Cysteine Endopeptidases , Disease Models, Animal , Enterovirus B, Human/drug effects , Heart/virology , Heart Function Tests , Male , Mice, Inbred DBA , Survival Analysis , Treatment Outcome , Viral Load
13.
Appl Biochem Biotechnol ; 162(5): 1471-82, 2010 Nov.
Article in English | MEDLINE | ID: mdl-20182816

ABSTRACT

The production of fermentable sugars from rice hull was studied by dilute acid pretreatment and enzymatic saccharification. Rice hull (15%, w/v) was pretreated by 1% (v/v) sulfuric acid at high temperature (120 approximately 160 degrees C) for 15, 30, 45, and 60 min, respectively. The maximum sugar concentration from rice hull in the prehydrolysate was obtained at 140 degrees C for 30 min, but the enzymatic saccharification yield from the corresponding pretreated rice hull is not high. To another aspect, the maximum enzymatic saccharification yield was achieved at 160 degrees C for 60 min, while the recovery of fermentable sugars was the poorest. To take account of fermentable sugars from pretreatment and enzymatic saccharification, the maximum yield of sugars was obtained only when rice hull was treated at 140 degrees C for 30 min. Under this condition, 72.5% (w/w) of all sugars generated from the raw material can be recovered. The kinetic study on the enzymatic saccharification of dilute acid pretreated rice hull was also performed in this work by a modified Michaelis-Menten model and a diffusion-limited model. After calculation by a linear and a non-linear regression analysis, both models showed good relation with the experimental results.


Subject(s)
Biotechnology/methods , Carbohydrate Metabolism , Cellulase/metabolism , Fermentation/physiology , Oryza/metabolism , Waste Products/analysis , Carbohydrate Metabolism/drug effects , Fermentation/drug effects , Hydrolysis/drug effects , Kinetics , Oryza/drug effects , Regression Analysis , Sulfuric Acids/pharmacology , Temperature , Thermogravimetry , Time Factors
14.
Bioresour Technol ; 99(2): 378-86, 2008 Jan.
Article in English | MEDLINE | ID: mdl-17320379

ABSTRACT

A microorganism hydrolyzing rice hull was isolated from soil and identified as Bacillus amyloliquefaciens by analysis of 16S rDNA and partial sequences of the gyrA gene, and named as B. amyloliquefaciens DL-3. With the analysis of SDS-PAGE, the molecular weight of the purified cellulase was estimated to be 54kDa. The purified cellulase hydrolyzed avicel, caboxymethylcellulose (CMC), cellobiose, beta-glucan and xylan, but not p-Nitrophenyl-beta-D-glucopyranoside (PNPG). Optimum temperature and pH for the CMCase activity of the purified cellulase were found to be 50 degrees C and pH 7.0, respectively. The CMCase activity was inhibited by some metal ions, N-bromosuccinimide and EDTA in the order of Hg(2+)>EDTA>Mn(2+)>N-bromosuccinimide>Ni(2+)>Pb(2+)>Sr(2+)>Co(2+)>K(+). The open reading frame of the cellulase from B. amyloliquefaciens DL-3 was found to encode a protein of 499 amino acids. The deduced amino acid sequence of the cellulase from B. amyloliquefaciens DL-3 showed high identity to cellulases from other Bacillus species, a modular structure containing a catalytic domain of the glycoside hydrolase family 5 (GH5), and a cellulose-binding module type 3 (CBM3).


Subject(s)
Cellulase/isolation & purification , Cellulase/metabolism , Oryza/microbiology , Plant Stems/microbiology , Amino Acid Sequence , Bacillus/enzymology , Base Sequence , Cellulase/genetics , Cloning, Molecular , DNA, Bacterial/genetics , DNA, Ribosomal/genetics , Electrophoresis, Polyacrylamide Gel , Enzyme Stability , Hydrogen-Ion Concentration , Kinetics , Molecular Sequence Data , Substrate Specificity , Thermodynamics
15.
J Environ Biol ; 27(2 Suppl): 317-22, 2006 May.
Article in English | MEDLINE | ID: mdl-17436517

ABSTRACT

The degradation of microcystin by adsorbed bacteria on GAC (granular active carbon) filter from a water treatment facility was investigated. Dominant bacteria isolated from GAC were indigenous microorganisms, Psuedomonas sp. and Flavobacterium sp. The direct exposure of dominant GAC bacteria to microcystins resulted in a significant reduction of microcystin levels in both shaking and static conditions (t-test; p < 0.01). In bacteria-treatments, the half-life of microcystin was 2.6-3.5 days in both conditions. Based on this result, approximately 9-10 days would be estimated for 90% or up to 18-21 days of 99% of toxin to be degraded. This biological degradation by the GAC bacteria in combination with existing purification systems has potential to increase the efficiency of water purification.


Subject(s)
Filtration/instrumentation , Flavobacterium/metabolism , Microcystins/metabolism , Pseudomonas/metabolism , Adsorption , Carbon , Half-Life
16.
J Environ Biol ; 26(1): 97-103, 2005 Jan.
Article in English | MEDLINE | ID: mdl-16114467

ABSTRACT

Cyanobacterial blooms and associated microcystins in hypertrophic stagnant West-Nakdong River were investigated at weekly intervals from April to August, 1999. Microcystis spp. accounted for over 85% of the numeric abundance of total phytoplankton. Microcystins were present in the blooms sampled between May and August. The peak of total microcystin (microcystin-LR + -RR) levels (maximum level; 612 microg g(-1)) was detected in the initial stage of the bloom (mid May), at the same time as high N/P ratio and high Microcystis biomass. This study indicated that total microcystins of this regulated river was positively correlated to Microcystis biomass, absolute nutrient concentration and TN/TP ratio.


Subject(s)
Cyanobacteria/growth & development , Ecosystem , Peptides, Cyclic/analysis , Rivers , Water Microbiology , Cyanobacteria/chemistry , Korea , Microcystins
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