• 대한기계학회논문집B
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• 제26권5호
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• pp.629-639
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• 2002

In-vitro flow characteristics downstream of a polyurethane artificial heart valve and a Bjork-Shiley Monostrut mechanical valve have been comparatively investigated in pulsatile flow using particle image velocimetry (PIV). With a triggering system and a time-delayed circuit the velocity distributions on the two perpendicular measurement planes downstream of the valves are evaluated at any given instant in conjunction with the opening behaviors of valve leaflets during a cardiac cycle. The regions of stasis and high shear stress can be found simultaneously by examining the entire view of the instantaneous velocity and Reynolds shear stress fields. It is known that high shear stress regions exist at the interface between strong axial jet flows along the wall and vortical flows in the central area distal to the valves. In addition. there are large stagnation or recirculation regions in the vicinity of the valve leaflet, where thrombus formation can be induced by accumulation of blood elements damaged in the high shear stress zones. A correlation between the unsteady flow patterns downstream of the valve and the corresponding opening postures of the polyurethane valve membrane gives useful data necessary for improved design of the frame structure and leaflet geometry of the polyurethane valve.

• 대한수의학회지
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• 제55권4호
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• pp.233-240
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• 2015

Although the effects of the rice bran have recently been investigated, there is no information regarding platelet physiology available. However, it is well known that fermented natural plants have a beneficial effect on cardiovascular diseases. Therefore, this study was conducted to investigate whether fermented rice bran extract (FRBE) with several plants (Artemisia princeps, Angelica Gigantis Radix, Cnidium officinale, and Camellia sinensis) affected agonist-induced platelet aggregation, and if so, what the underlying mechanism of its activity was. We performed several experiments, including in vitro platelet aggregation, intracellular calcium concentration and adenosine triphosphate release. In addition, the activation of integrin ${\alpha}_{II}b{\beta}3$ was determined using fibrinogen binding. Thrombus formation was also evaluated in vivo using an arterio-venous shunt model. The FRBE inhibited collagen-induced platelet aggregation in a concentration-dependent manner. FRBE significantly and dose dependently attenuated thrombus formation using rat arterio-venous shunt. FRBE suppressed the intracellular calcium mobilization in collagen-stimulated platelets. We also found that FRBE inhibited extracellular stimuli-responsive kinase 1/2, p38-mitogen-activated protein kinases and c-Jun N-terminal kinase phosphorylation. These results suggested that FRBE inhibited collagen-induced platelet aggregation, which was mediated by modulation of downstream signaling molecules. In conclusion, FRBE could be developed as a functional food against aberrant platelet activation-related cardiovascular diseases.

• 생약학회지
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• 제30권3호
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• pp.231-237
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• 1999

About forty sea weeds were screened for their inhibitory effects against prolyl endopeptidase, tyrosinase and thrombus coagulation. Out of them, methanolic extract of Ecklonia cava, Sargassum patens, Sargassum hemiphyllum, Sargassum thunbergii, Sargassum singgildianum, Hizikia fusiformis, and Ishige okamurae inhibited more than 90% of prolyl endopeptidase activity at 40 ppm. Sargassum siliquastrum and Ecklonia cava exhibited 51% and 76% of inhibitory activity against tyrosinase at 40 ppm, respectively. In APTT assay system, Sargassum singgildianum, Pterocladia capilacea and Hizikia fusiformis delayed coagulation of thrombus about two times (210, 211, and 198% over control at ca 367 ppm, respectively) and in TT assay, Lomentaria catenata, Laurencia okamurae, and Hizikia fusiformis did most effectively (216,197, and 251% at ca 367 ppm, respectively).

• 대한수의학회지
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• 제56권2호
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• pp.67-74
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• 2016

Tomato extract has been shown to exert antiplatelet activity in vitro and to change platelet function ex vivo, but with limitations. In this study, antiplatelet activity of water soluble tomato concentrate (Fruitflow I) and dry water soluble tomato concentrate (Fruitflow II) was investigated using rat platelets. Aggregation was induced by collagen and adenosine diphosphate and granule-secretion, $[Ca^{2+}]_i$, thromboxane B2, cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP) levels were examined. The activation of integrin ${\alpha}_{IIb}{\beta}_3$ and phosphorylation of signaling molecules, including mitogen-activated protein kinase (MAPK) and PI3K/Akt, were investigated by flow cytometry and immunoblotting, respectively. Prothrombin time (PT) and activated partial thromboplastin time (aPTT) were examined. Moreover, in vivo thrombus weight was tested by an arteriovenous shunt model. Fruitflow I and Fruitflow II significantly inhibited agonist induced platelet aggregation, adenosine triphosphate and serotonin release, $[Ca^{2+}]_i$, and thromboxane B2 concentration, while having no effect on cAMP and cGMP levels. Integrin ${\alpha}_{IIb}{\beta}_3$ activation was also significantly decreased. Moreover, both concentrates reduced phosphorylation of MAPK pathway factors such as ERK, JNK, P38, and PI3K/Akt. In vivo thrombus formation was also inhibited. Taken together, these concentrates have the potential for ethnomedicinal applications to prevent cardiovascular ailments and can be used as functional foods.

• 한국임상수의학회지
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• 제26권3호
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• pp.268-272
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• 2009

An-11-year-old male Shih-tzu was admitted to emergency care unit of Haemaru Referral Animal Hospital with signs of dyspnea, anuria and depression. There were abnormalities on complete blood count and serum chemistry included leukocytosis with mild left shift, mild azotemia, and increased ALT activity. Fluid therapy(0.9% saline, 40 ml/hr) and antibiotics were immediately initiated. The patient began to vomit after 5 hours' rest and pale mucous membrane, bradycardia, and hypertension were noted. Abdominal ultrasonography revealed enlarged left adrenal gland and thrombus in caudal vena cava(CVC). Result of ACTH stimulation test was normal. Cytology of ultrasound-guided FNA smears showed numerous naked nuclei, which was suggestive of adrenal medullar tumor. Concentrations of 24 hour urine metanephrine and normetanephrine was moderately increased compared to those of a control dog. Adrenal mass was surgically removed, and biopsy of the CVC mass was obtained. After surgery the patient began to recover but the dog acutely developed cardiopulmonary arrest and died. On histopathology the adrenal mass and biopsy of the CVC mass were consistent with pheochromocytoma. On electron microscopic view norepinephrine specific granules were found in the cytoplasm of tumor cells.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제22권1호
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• pp.22-32
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• 2000

Purpose : Histopathologic observation was performed in order to determine which type of suture material is superior in microvascular anastomoses. Materials & Methods : The interrupted end to end anastomosis of the transected carotid arteries of 105 Sprague-Dawley rats, weighing 180 to 200g, were performed using 9-0 polypropylene ($Prolene^{TM}$, Ethicon, U.K.), 9-0 polyglactin 910 monofilament($Vicryl^{TM}$, Ethicon, U.K.), and 9-0 polyamide($Ethilon^{TM}$, Ethicon, U.K.) under intramuscular Ketamine and Xylazine anesthesia(5mg/100g). In all cases, 10 to 12 sutures were placed to complete the anastomoses. The specimens were obtained at 1, 2, 3 days, and 1, 2, 4 and 6 weeks after the surgery and prepared with H&E and Van-Gieson stains and investigated the histologic changes in anastomotic sites under light microscope. The histologic changes we were concerned about were followings- thrombus formation, intimal edema, infiltration of inflammatory cells in media and adventitia, proliferation of endothelial cells and subintimal hyperplasia. Results : 1. All of the anastomosed arteries were patent when they were exposed for examination. 2. Thrombus formation and intimal edema were most severe in Vicryl group, followed by Ethilon, Prolene group in order. 3. The inflammatory cells infiltrated to the media and the adventitia most severely in Ethilon group, followed by Vicryl, Prolene group in order. 4. There was little difference in proliferation of endothelial cells in each group. 5. Subintimal hyperplasia was greater in Vicryl group than the others, but there was no significant difference between the Prolene and Ethilon groups. Conclusions : On the basis of these observations, we could conclude that Prolene may be the better suture material for microvascular anastomoses regarding the tissue responses than Ethilon and Vicryl.

• 한국임상수의학회지
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• 제24권2호
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• pp.255-259
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• 2007

A 6-year-old, intact male, mongrel dog with yellowish urine, anorexia, depression was referred to the Veterinary Medical Teaching Hospital of the Chungnam National university. Immune mediated hemolytic anemia (IMHA) was diagnosed by clinical signs, physical examination, laboratory tests (CBC, serum chemistry, Coombs' test, autoagglutination test and urinalysis) and diagnostic imaging (X-ray and ultrasonography). Clinical signs were improved after combined immune-suppressive therapy (prednisolone and cyclosporine) and prophylactic heparin therapy. A thrombus ($4cm{\times}1cm$) was observed in the right ventricle by autopsy. Combined therapy and supportive care (antithrombolytic agent and acupuncture) were effective in a dog with IMHA.

• Pediatric Infection and Vaccine
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• 제26권1호
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• pp.60-65
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• 2019

항인지질항체는 자가면역 질환에서 발생할 수 있고, 때로는 마이코플라즈마와 같은 감염 후에도 발생할 수 있다. 그러나 마이코플라즈마 폐렴 후 항인지질항체의 발현과 혈전의 발생은 매우 드물게 보고되어왔다. 본 8세 환아는 마이코플라즈마 폐렴 입원 치료 중 손가락의 변색 및 감각 저하가 발생하였고 혈액검사 결과 항인지질항체 양성으로 확인되었다. 이로 인해 상완동맥 혈전증이 발생하여 혈전제거술을 시행하여 제거하였다. 양성이었던 항인지질항체는 5개월 내 다시 정상화되었다. 마이코플라즈마 폐렴의 합병증은 피부 병변을 포함하여 체내 많은 장기에 다양한 증상을 보이지만, 그 중 항인지질항체의 발현으로 인한 혈전의 발생은 치명적이므로, 마이코플라즈마 폐렴의 치료에 있어 고려해야 할 합병증의 사례를 보고한다.

• Journal of Korean Neurosurgical Society
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• 제64권1호
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• pp.60-68
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• 2021

Objective : Until recently, the transfemoral approach (TFA) was used as the primary method of arterial approach in acute ischemic stroke (AIS). However, TFA resulted in longer reperfusion times and worse outcomes in the mechanical thrombectomy (MT) of patients with complex aortic arches and significant carotid tortuosity. We found that the transradial approach (TRA) is a more favorable alternative approach for MT in such cases. Methods : We performed a retrospective review of our institutional database to identify 202 patients who underwent MT for AIS between February 2015 and December 2019. Patient characteristics, cause of TFA failure, procedure time, intra-procedural complications, and outcomes were recorded. Results : Eleven (5.4%) of 202 patients, who underwent MT for AIS, crossed over to TRA for recanalization, and eight (72%) of 11 achieved successful recanalization (≥modified Treatment in Cerebral Infarction 2b). The mean age (mean±standard deviation [median]) was 82.3±6.6 (76) years, and five of the 11 patients were male. The last seen normal to puncture time was 467.9±264.72 (264) minutes; baseline National Institutes of Health Stroke Scale score was 28.9±14.5 (16). Six (55%) of the 11 patients had right vertebrobasilar occlusions, and the remaining five (45%) had anterior circulation occlusive disease. The time from groin puncture to final recanalization time (overall procedural time) was 78.0±20.1 (62) minutes. The mean crossover time from TFA to TRA was 45.2±10.5 (41) minutes. The mean time from radial puncture to final recanalization was 33.8±10.5 (28) minutes. Distal thrombus migration events in previously unaffected territories occurred in 3/8 patients (37%). At 90 days, three patients (28%) had a favorable clinical outcome. Conclusion : Although rare, failure of TFA has been known to occur during MT for AIS. Our results demonstrate that TRA may be an alternative option for AIS intervention for select patients with subsequent timely revascularization. However, the incidence of distal thrombus migration was high, and the first puncture to reperfusion time was prolonged because of the time taken for the crossover to TRA after failure of TFA. This study provides some evidence that the TRA may be a viable alternative option to the TFA for MT of AIS.

• Journal of Microbiology and Biotechnology
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• 제31권2호
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• pp.327-337
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• 2021

Fibrinolytic enzymes with a direct mechanism of action and safer properties are currently requested for thrombolytic therapy. This paper reports on a new enzyme capable of degrading blood clots directly without impairing blood coagulation. This enzyme is also non-cytotoxic and constitutes an alternative to other thrombolytic enzymes known to cause undesired side effects. Twenty-four Bacillus isolates were screened for production of fibrinolytic enzymes using a fibrin agar plate. Based on produced activity, isolate S127e was selected and identified as B. subtilis using the 16S rDNA gene sequence. This strain is of biotechnological interest for producing high fibrinolytic yield and consequently has potential in the industrial field. The purified fibrinolytic enzyme has a molecular mass of 27.3 kDa, a predicted pI of 6.6, and a maximal affinity for Ala-Ala-Pro-Phe. This enzyme was almost completely inhibited by chymostatin with optimal activity at 48℃ and pH 7. Specific subtilisin features were found in the gene sequence, indicating that this enzyme belongs to the BPN group of the S8 subtilisin family and was assigned as AprE127. This subtilisin increased thromboplastin time by 3.7% (37.6 to 39 s) and prothrombin time by 3.2% (12.6 to 13 s), both within normal ranges. In a whole blood euglobulin assay, this enzyme did not impair coagulation but reduced lysis time significantly. Moreover, in an in vitro assay, AprE127 completely dissolved a thrombus of about 1 cc within 50 min and, in vivo, reduced a thrombus prompted in a rat tail by 11.4% in 24 h compared to non-treated animals.