Coagulation Technique Research Articles

Disinfection by-product precursors reduction by various coagulation techniques in Istanbul water supplies

Coagulation process can be used to control natural organic matter (NOM) during drinking water production. The effectiveness of the coagulation process appeared to depend on the pH of coagulation rather than coagulant dosages. Jar tests conducted with depressed pH levels at different coagulation conditions removed more dissolved organic carbon (DOC) than those at moderate pH levels. For low DOC waters, like Omerli Lake Water (OLW), additional treatment would be necessary to achieve enhanced removal of NOM. In this study, three different coagulation techniques were used to remove disinfection by-products (DBP) precursors from three Istanbul surface water supplies. Jar test results indicate that optimize coagulation (OC) can enhance the removal of DBP precursors, and the removal of DOC could be improved from the current average of 15% to an average of 56% at the three sites tested. At lower pH, ferric coagulants generally performed better for removal of DBP precursors than did alum.

Controlled Nano-Oxide Layer Coating on Fine Particles with Multiple Optical-Electrical Functions

SiO2 core/TiO2 shell composite particles were synthesized by four different heterogeneous coagulation techniques. The configurations of the composite particles and the microstructure of assembly were characterized by SEM and TEM. The colloidal stability of nano-particles was also computer-simulated by a discrete element method (DEM) in consideration of Brownian motion occurring on the nano-particles. The results indicated that uniform adsorption of the fine particle absolutely needed fine tuning of surface charging conditions and processing steps.

Preparation of P(AN–MMA) microporous membrane for Li-ion batteries by phase inversion

A novel process was proposed for preparation of microporous poly(acrylonitrile–methyl methacrylate) (P(AN–MMA)) membranes by phase inversion techniques using ultrasonic humidifier. Being prepared by dissolving the polymer (PAN–MMA) in the N, N-dimethylformamide (DMF) solution with mechanical stirring, the homogenous casting solution was cast onto a clean glass plate. Successively, the glass plate was exposed to the water vapor produced by ultrasonic humidifier, inducing the phase inversion. It is found the pore size is much more uniform across the cross-section of the membrane than that of the porous membrane prepared by conventional water bath coagulation technique. The microporous membranes were directly obtained after the washing and drying. It had about 1–5 μm of pores and presented an ionic conductivity of 2.52 × 10 −3 S/cm at room temperature when gelled with 1 M LiPF 6/EC-DMC (1:1 vol.%) electrolyte solution. The test cells with the gel electrolytes prepared from as-prepared microporous membranes showed stable cycling capacities, indicating that the microporous membrane, which was prepared from cheap starting materials acrylonitrile and methyl methacrylate, can be used for the gel electrolyte of lithium batteries.

Comparative experimental study of argon plasma and bipolar coagulation techniques

Argon plasma coagulation (APC) is based on the principle of ionised argon creating conductive plasma between an activating electrode and tissue surface and is used as an effective alternative coagulation technique in various surgical disciplines. This trial aims to compare thermal injury in rat brain caused by APC and conventional bipolar coagulation technique. A controlled study design with constant power setting and application time was established. Twenty rats were randomised into the APC and bipolar groups. Each group of ten rats had 20 treated lesions. Early and late histopathological changes, as well as maximum extent of the lesion after 48 hours (h) and 12 days were studied in overall 20 lesions. Although the maximum depth of the lesions was different in APC (2.2 mm) and bipolar (1.8 mm) groups after 48 h, this did not achieve statistical significance (p=0.151). The superficially coagulated area was significantly larger after APC compared with the bipolar technique at the 48 h time point (p=0.032). After twelve days there were no differences in penetration depth (p=0.310) or coagulated area (p=0.222). Tissue defects after APC application on rat brains were comparable to conventional bipolar technique in this trial. The results suggest that argon plasma coagulation (APC) is an effective coagulation technique.

Cortical anastomotic veins occlusion in the rat including the assessment of cerebral swelling

A rat model composed of the sacrifice of the anterior and posterior cortical anastomotic veins by microsurgical techniques was used for the assessment of brain swelling. Twenty male, 15-week-old Sprague–Dawley rats were used in this animal experiment. Small burr-holes were made over the anterior (the intersection of the line drawn from the posterior border of the orbital rim and the line drawn along the para-midline to the superior sagittal suture) and posterior (inferior point of the posterior end of the zygomatic arch) anastomotic veins. After performing a final inspection and describing the venous vessels, they were sacrificed using bipolar coagulation technique and micro-scissors. Specimens were evaluated using histopathological approach, albumin immunostaining technique and a stereological method. Hemispheric swelling, midline shift, brain oedema, subcortical petechial haemorrhagia, ischemia and necrosis were histopathological findings observed in this experimental study. The albumin immunostaining study demonstrated disrupted areas of the blood–brain barrier in the operated hemisphere. Stereological volumetric analysis revealed an 8% brain swelling in the operated hemispheres compared with unoperated ones. Our results suggest that the sacrifice of the anterior and posterior anastomotic veins may be used as an experimental rat model in the evaluation of brain damage and swelling caused by the occlusion of the venous anastomotic outflow.

Prospective Evaluation of Two Modes of the New Vio 300D-Argon-Plasma-Coagulation (APC)-System for Palliation of Obstructing Gastrointestinal Tumors: Forced-APC Versus Pulsed-APC

Introduction: The palliative effect of endoscopic thermal techniques (Nd:Yag-laser, APC) for the treatment of obstructing gastrointestinal (GI) tumors has been proven for years. APC is a thermal coagulation technique that uses ionized argon to transmit high-frequency electrical current, contact free, to tissue. However, data from the new APC -VIO -300D -system with amplified power settings and different application modes is lacking. The aim of the study was to compare the new mode of PULSED APC (10 argon beams/sec.) vs. the well-known FORCED APC mode. Methods: Patients (pts.) with symptomatic obstructing tumors of esophagus, stomach and rectum were enrolled in the study. The palliative effect was assessed by evaluating the size of the restored lumen (1/3, 2/3, complete restoration), length of the stenosis (cm), and time and number of APC-sessions. The range of energy output was 40-130 Watt (median FORCED 83 Watt; median PULSED 76 Watt). A total number of 83 pts. were included (FORCED 44 pts., PULSED 39 pts.). Results: The overall response rate after treatment was 87% (38/44 pts.) with FORCED APC vs. 83% (32/39 pts) with PULSED APC. Complete restoration of the lumen: FORCED APC 16% (7/44) vs. PULSED APC 9% (3/39). Restoration >2/3 of the lumen: FORCED APC 55% (24/44) vs. PULSED APC 52% (20/39). Restoration >1/3 of the lumen: FORCED APC 16% (7/44) vs. PULSED APC 23% (9/39). Restoration of the lumen <1/3 was seen in 13.6% (FORCED APC) vs. 18% (PULSED APC). The median length of the tumors was shortened with FORCED APC by 2.4 cm and with PULSED APC by 2.5 cm. Overall, a median number of 2.2 treatment sessions were necessary (FORCED APC 2.0, PULSED APC 2.6). The tumor debulking effect was achieved in a significantly shorter median application time (in minutes) with FORCED APC (FORCED APC 13 min. vs. PULSED APC 19.5 min.) (p = 0.03). Major complications occurred in 10.5% of pts. with FORCED APC vs. 7% of pts. with PULSED APC. Conclusion: There was no significant difference in overall local tumor response and major complication rate between the modes. However, the local palliative response was achieved significantly earlier with FORCED APC. Therefore high-energy APC (>70 Watt) with the VIO -300D -system could become an alternative option to established thermal vaporization techniques in obstructing GI-tumors.

Treatment of watermelon stomach

Watermelon stomach (WMS), or gastric antral vascular ectasia, is an uncommon but clinically important cause of chronic occult or overt gastrointestinal (GI) blood loss. Patients typically present with symptomatic anemia and hemoccult positive stools. Although the diagnosis is based primarily on the typical endoscopic appearance, the lesion may be overlooked on initial evaluation or interpreted as "gastritis." Gastric biopsy may be helpful in confirming the diagnosis by showing vascular ectasia, typically without inflammation. WMS is idiopathic but is often associated with autoimmune diseases or cirrhosis of the liver. The majority of patients with classic WMS are elderly and female. In contrast, there is no gender predominance with the diffuse pattern associated with cirrhosis. General supportive care includes transfusion of blood products as necessary to control symptomatic anemia and coagulopathy, iron replacement therapy by oral or parenteral routes, identification and treatment of iatrogenic (eg, warfarin) or hereditary (eg, von Willebrand's disease) coagulopathy, and avoidance of substances that might cause gastric mucosal damage and/or bleeding (eg, aspirin, NSAIDs, alcohol). The goals of therapy are to eliminate or decrease the need for blood transfusions, hospitalization, office visits, and endoscopic therapy sessions aimed at cessation of GI blood loss and resolution of symptomatic anemia. Multipolar electrocoagulation is our preferred technique for endoscopic ablation of WMS. A 10-Fr probe (3.2 mm in diameter) is used at a generator setting of 12 to 16 W. Pulse duration can be as short as 1 to 2 seconds if a pinpoint coagulation technique is used, or continuous if a paint-stroke technique is used to coagulate all vascular stripes in the classic WMS pattern or as many small lesions as possible in the diffuse type. Other techniques we currently use are argon plasma coagulation (APC) or heater probe. In the past, lasers (neodymium: yttrium-aluminum-garnet , KTP, or argon) were successfully used for such treatments. An initial treatment interval of 4 to 8 weeks should allow for interim healing of iatrogenic ulcers. Patients are routinely given standard doses of available proton-pump inhibitors (PPIs) to facilitate healing of iatrogenic ulcers and to prevent secondary bleeding. The treatment interval can be gradually lengthened as the long-term goals of obliteration of angiomata and resolution of anemia are reached. Side effects may include iatrogenic ulceration at the site of treatment, bleeding, and transient abdominal pain. Antral scarring (after APC or Nd:YAG laser) and hyperplastic polyps have also been reported after endoscopic treatment of classic WMS. Surgical antrectomy is very effective in the prevention of bleeding but has substantial (5% to 10%) mortality in older patients with comorbidity and is now reserved for endoscopic failures.

DIAGNOSTIC USE OF THE PROTEIN C ACTIVATOR FROM AGKISTRODON CONTORTRIX

Disturbances within the protein C pathway due to coagulation factor V Leiden mutation and deficiency of protein C or protein S are the most frequent abnormalities in hereditary thrombophilia (hypercoagulable states). Furthermore, acquired dysfunctions of the protein C system may predispose an individual to an increased thrombotic risk. For diagnostic or research purposes, abnormalities of the protein C natural anticoagulant system are based on measuring protein C, protein S, and activated protein C resistance. Most of the assays contain the protein C activator Protac® from Agkistrodon contortrix contortrix (southern copperhead). Unlike the physiological, thrombin-catalyzed protein C activation reaction that requires thrombomodulin as a cofactor, Protac® directly converts the zymogen protein C into the catalytically active form that can easily be determined by means of coagulation or chromogenic substrate techniques. Protein C activators have been detected in several snake venoms. Most of them have been purified from venom of snake species belonging to the Agkistrodon or Gloydius genus. Due to its features, the fast-acting protein C activator Protac® has found a broad application in assays for research and in clinical practice to identify patients with defects of the protein C system.

Presence of trihalomethanes in drinking water plants in Nicaragua

The impact of enhanced coagulation on the formation of trihalomethanes (THMS) from drinking water was studied in four treatment plants in Nicaragua. Enhanced and conventional coagulation techniques ...

Study on the technique of microwave coagulation on hemostasis in the operation of liver cancers

目的 探讨微波固化在肝脏手术中的止血效果.方法100例肝癌切除手术患者随机分为两组,微波止血组63例,应用针型微波发射极对肝脏做植入式微波固化,结合分步阻断肝血流法切肝.对照组37例,用传统的肝血流阻断法切肝.结果微波固化后的肝脏在切割时几乎处于无渗血状态.不规则性肝切除术中,微波止血组39例,术中出血(136.92±42.27)ml;对照组22例,术中出血(276.36±68.07)ml,两组间差异有显著意义(P＜0.01).规则性肝段肝叶切除术中,微波止血24例,术中出血(303.54±80.55)ml;对照组15例,术中出血(490.67±113.10)ml,两组间差异有显著意义(P＜0.01).结论微波固化在肝癌切除术中止血效果显著,结合分步阻断肝血流法切肝,可缩短肝缺血时间,减轻术后肝功能损害,提高肝癌切除率。

Selection of ferrite powder for thermal coagulation therapy with alternating magnetic field

Selection of ferrite powder was carried out to realize a thermal coagulation technique in which tumors are locally heated by an application of alternating magnetic field from external coils. Magnesium ferrite (MgFe2O4) showed the largest increase in temperature (ΔT) under an alternating magnetic field in all the ferrites examined. For all the samples, ΔT value under alternating magnetic field was increased with an increase in frequency (200–500 kHz). The heating ability for the Mg-ferrite was ca. 1.4 W/g under alternating magnetic field of 4.0 kA/m (200 W, 370 kHz). The heating ability in alternating magnetic field was clearly depended on the magnitude of the hysteresis loss for the ferrite powder.

No clip, no ligature laparoscopic appendectomy.

Laparoscopic appendectomy (LA) is one of the common procedures being carried out in general surgery. The technique of bipolar coagulation (BC) has been effectively employed in obstetric and gynecologic procedures but has not been used for intestines. We present the technique of LA using BC at our center. The technique consisted of identifying the appendix and coagulating the appendicular stump with bipolar coagulation until there were no bubbles at the cautery site, and a constriction ring formed at the site of coagulation. Sixty patients with acute or recurrent appendicitis underwent the procedure. The median duration of BC was 90 seconds. The median duration of surgery was 25 minutes, postoperative hospital stay was 3 days, and time to oral feeds was 12 hours. The technique of laparoscopic appendectomy by bipolar coagulation is very simple and economical. The duration of surgery is less than for the standard technique of laparoscopic appendectomy; no clip applicators, needle holders or knot pushers are required, and no foreign materials like ligatures or clips are needed.

Development of an in vitro model to evaluate innovative electrosurgical high-frequency coagulation techniques

Development of an in vitro model to evaluate innovative electrosurgical high-frequency coagulation techniques

Wide Endoscopic Mucosal Resection in Esophagus Using Modified Needle Knife: Porcine Model Experiment

Purpose: Endoscopic mucosal resections are increasingly being applied for diagnosis and treatment of esophageal lesions including malignancies and Barrett's high-grade dysplasia. One of the limitations of the current techniques is the size of the resection due to the accessory dimension. In this study, we investigated the feasibility and safety of wide mucosal resection in esophagus using a modified needle knife in porcine model. Methods: Four pigs (30∼50kg) were used after institutional animal protocol approval. Under general anesthesia, upper endoscope (either GIF-Q160 or GIF-2T160) was advanced orally to distal esophagus. Sterile saline with 1:100,000 to 1:200,000 epinephrine (+ India ink) was injected submucosally (20∼60cc total). After initial marking with a needle knife, horizontal mucosal incision at the distal and proximal levels of rectangular region in distal esophagus was performed using an insulated-tip modified needle knife (IT-knife, Olympus/Olympus America) at 40W cut current with Blend 1 (Valleylab). This was followed by longitudinal mucosal incision at the lateral borders. Using ample saline injections, submucosal incision with the IT-knife was continued. The residual adherence at the end was disrupted with polypectomy snare in standard fashion. Simple coagulation techniques were applied for local bleeding control if needed. Post-procedurally, lansoprazol 60 mg was given orally. The pigs were fed soft diet and observed for 24 hours for any signs of immediate complications. Pigs were sacrificed thereafter, and gross inspection of the distal esophagus and the adjacent regions was completed. Results: The longitudinal lengths of 3∼5 cm rectangular esophageal mucosal resections were performed. Spans of 1/2 circumference (1), 3/4 circumference (2), and circumferential mucosal resections (1) were completed successfully. Minimal bleedings encountered during the procedure were all controlled with epinephrine injection or simple coagulating current application. During the 24-hour observation period, none of the pigs showed evidences of bleeding, infection, or perforation. This was confirmed with post-mortem examination of the distal esophagus. Behavior of the pigs post-resection was essentially unchanged from prior to the procedure. Conclusions: Endoscopic wide mucosal resection in esophagus is feasible and appears to be safe. Potential application in Barrett's high-grade dysplasia and early cancer warrants further study of this technique.

Numerical study of temperature distribution in tissue for thermal coagulation therapy

Abstract Thermal coagulation technique in which tumors are locally heated up to 60–80°C can be realized by application of AC magnetic field from external coils to tumors covered with magnetic particles. We study numerically the temperature distribution in living tissue containing ferrite powder. With this temperature distribution, we calculate the magnitude of damaged region in tissue including a tumor and show a relation between tumor radii and the power of AC magnetic field.

Heating ferrite powder with AC magnetic field for thermal coagulation therapy

Abstract In order to realize a thermal coagulation technique in which tumors are locally heated up to 60–80°C by inductive heating and necrotized, selection of ferrite powder and frequency are performed. We investigate the heating properties by applying AC magnetic field for various ferrite powders (micrometer size of the particles). The temperature rise for Mg-ferrite (MgFe 2 O 4 ) powder is the largest around 360 kHz in our samples. It has sufficient heating ability for thermal coagulation therapy against cancer.

Biomehanicke karakteristike tkiva kicmene mozdine - osnov za razvoj modifikovane tehnike DREZ operacije

Mechanical properties of the spinal cord tissue--biological basis for the development of the modality of the DREZ surgery lesioning technique Succesful treatment of the chronic neurogenic pain of spinal cord and cauda equina injury origin remains a significant management problem. The mechanism of this pain phenomenon has been shown to be related to neurochemical changes that lead to the state of hypereactivity of the second order dorsal horn neurons. The DREZ surgery (Dorsal Root Entry Zone lesion), designed to destroy anatomy structures involved in pain generating thus interrupting the neurogenic pain mechanism, as a causative procedure in treating this chronic pain, has been performed by using different technical modalities: Radiofrequency (RF) coagulation technic, Laser, Ultrasound and Microsurgical DREZotomy technic. The purpose of the study was to assess the possibility for the establishment of the lesioning technic based on the natural difference in the mechanical properties between the white and gray cord substance. We experimentally deteminated mechanical properties of the human cadaveric cord white versus gray tissue for the purpose of testing possibility of selective suction of the dorsal horn gray substance as a DREZ lesioning procedure. Based on the fact of the difference in tissue elasticity between white and gray cord substance we established a new and simple DREZ surgical lesioning technique that was tested on cadaver cord. For the purpose of testing and comparing the size and shape of the DREZ lesion axchieved the DREZ surgery has been performed on cadaver cord by employing selective dorsal horn suction as a lesioning method. After the procedure cadaver cord underwent histological fixation and analysis of the DREZ lesions achieved. Our result revealed that the white cord substance with longitudinal fiber structure had four time higher dynamical viscosity than gray substance of local neuronal network structure (150 PaS versus 37.5 PaS) that provided possibility for the safe and selective suction of the gray substance of the dorsal horn. Technic includes incision of the dorsolateral sulcus according to Sindous Microsurgical DREZotomy technic than suction under visual control of the dorsal horn gray matter using succer adopted from the lumbar puncture nidle. Operative experimental testing and hystological analysis confirmed expected size and shape of the DREZ lesion performed by dorsal horn suction as DREZ lesioning technique. The utility, selectivity and safety of this technic has been provided by the natural mechanical properties of the cord tissue itself. Application of the Dorsal horn suction as a DREZ lesioning in humans confirmed this technic as a safe and reliable DREZ lesioning method.

Argon plasma coagulation in the treatment of nonallergic hypertrophic inferior nasal turbinates

Purpose: Various surgical procedures have been recently proposed for the treatment of hypertrophic inferior nasal turbinates as a result of the advances made in medical technology and growing public demand for minimally invasive therapies. The aim of this study was to evaluate the safety and efficacy of the argon plasma coagulation technique for inferior turbinate reduction in a homogeneous series of patients with nonallergic inferior turbinate hypertrophy. Material and methods: Twenty symptomatic patients underwent argon plasma coagulation surgical treatment under local anesthesia and were clinically followed up after 1 month and then every 3 months (anterior rhinoscopy and nasal endoscopy). Diagnostic evaluations using active anterior rhinomanometry were made after 3 and 12 months. Results: All of the patients reported a postoperative improvement in nasal swelling and patency. No postoperative complications were observed. Rhinomanometry after 12 months showed a reduction in mean total resistance from the pretreatment level of 1.06 Pa s/cm 3 to 0.49 Pa s/cm 3. There was also a statistically significant reduction in nasal resistance for each of the investigated conditions (inspiration and expiration in orthostatism and clinostatism). Conclusions: Argon plasma coagulation is a safe and efficacious procedure for the minimally invasive treatment of inferior turbinate hypertrophy, which can be performed under local anesthesia in an outpatient setting with little discomfort for the patient.

Atraumatic bloodless removal of intramedullary hemangioblastomas of the spinal cord

The goal of this study was to summarize the author's personal experience in the surgical treatment of 19 patients with intramedullary spinal cord hemangioblastomas. All cases were from the author's private practice and were treated between 1967 and 1990. In all cases the intramedullary hemangioblastomas were totally removed by using a unique microsurgical technique of bipolar coagulation, which is fully described in this paper. A bipolar forceps was used to shrink each tumor and detach it from its feeding and draining vessels. Tumor resection was successfully accomplished in all patients. Blood loss was minimal, averaging less than 100 ml, and what little bleeding occurred did so during laminotomy or laminectomy. No bleeding occurred during tumor removal, and no transfusions were given. All patients were symptomatic preoperatively, and all recovered or improved following surgery. The technique described in this paper makes tumor removal safe, effective, and relatively easy.

The usefulness of prevention consolidation therapy of esophageal varices using an argon plasma coagulation technique

Background and study aim: esophageal variceal ligation (EVL) has been spread widely as a simple and effective method for treating esophageal varices. However, in view of the unacceptably high rate of recurrence associated with this technique, the availability of other supplemental consolidation therapies has been earnestly desired. Under these circumstances, attempts such as endoscopic injection sclerotherapy (EIS) have been made for this particular therapeutic purpose. In the current study, we tested the clinical usefulness and safety of the argon plasma coagulation technique (APC). Patients and methods: 11 patients with imminent signs of esophageal varix rupture in our hospital were subjects in the present study. Before APC was performed, these patients underwent EVL with consequent improvement of esophageal varices from F3 (largest sized varices) to disappear or F1 (straight). Results: the patients were followed up for a mean post-treatment period of 637.4 (SD ±56.5) days, and no obvious recurrence of varices in the so-called critical area was noted. In addition, no serious complications were observed. Conclusion: our current clinical study has demonstrated that APC may be an effective prevention consolidation therapy after EVL without serious complications.