多曲方丝弓技术矫治成人前牙开

目的：分析多曲方丝弓技术在矫治成人前牙开病例中的作用。方法：选取11例（男6例,女5例）以多曲方丝弓技术矫治的成人开病例,年龄18.2～21.5岁,平均19.2岁,前牙开范围2.5～5.5mm,平均3.8mm。矫治前均进行了上、下颌第三磨牙的拔除。采用配对t检验对矫治前、后的X线头颅侧位片的测量数值进行分析比较。结果：11例患者均取得了满意的疗效：开解除,前牙覆盖、覆正常,尖牙及磨牙关系Ⅰ类。矫治前、后具有统计学显著性差异的项目：ANB,U1-SN,L1-MP,U6-SN,U6-PP（mm）,L6-MP,L6-MP（mm）等均明显减小,L1-MP（mm）,U1-L1,OB（mm）等均明显增加,SNA、SNB、SN-MP、FH-MP,ODI、APDI等均无显著性差异,说明矫治后上、下后牙均向远中竖直,上、下前牙均有伸长及舌向倾斜移动,骨骼状态没有明显改变,以牙齿代偿性变化为主。结论：多曲方丝弓矫治技术主要通过改善牙齿三维方向的位置,可以有效矫治成人前牙开。     

应用多曲方丝弓技术矫治成人前牙重度深覆

目的探讨多曲方丝弓技术在治疗成人前牙重度深覆中的作用。方法选择20例成人前牙重度深覆患者,使用多曲方丝弓矫治深覆。治疗前后拍摄X线头颅侧位定位片,并进行X线头影测量分析。结果U1A—PP平均减小了1.75 mm,L1A—MP平均减小了1.67 mm,U6—PP平均增加了1.53 mm,L6—MP平均增加了1.53 mm,说明多曲方丝弓能压低前牙,升高后牙。结论应用多曲方丝弓技术,能压低前牙,升高后牙,对于成人前牙重度深覆是一种快速、有效整平牙弓的方法。     

多曲方丝弓技术矫治恒牙期骨性Ⅲ类错的临床研究

目的:研究多曲方丝弓技术矫治恒牙初期骨性Ⅲ类错的临床疗效,为临床治疗提供一定参考。方法:选取应用MEAW技术治疗恒牙初期骨性Ⅲ类错畸形的患者12例,测量矫治前后的X线头颅侧位定位片并进行配对t检验以评估疗效。结果:MEAW技术矫治恒牙期骨性Ⅲ类错主要是通过牙齿的移动和牙槽骨的改建。通过A点的前移,下磨牙的直立和远中移动使磨牙关系和前牙覆盖关系明显改善。下前牙舌向移动和升高,平面变平。结论:MEAW可以有效矫治恒牙初期轻、中度骨性Ⅲ类错。     

骨性安氏Ⅱ类1分类错的拔牙矫治

目的:通过X线头影测量探讨方丝弓技术拔牙矫治恒牙期骨性安氏Ⅱ类1分类错的临床疗效。方法:对10名前牙深覆盖达到8～11mm且ANB平均为7.4°伴Ⅲ°深覆的恒牙期患者,采用方丝弓技术进行矫治,均拔除4个第一双尖牙,并对所有患者正畸治疗前后进行头影测量分析。结果:10例患者治疗后覆盖、覆牙合均达到正常,NA-PA平均减少4.4°,ANB减小2.3°,SNA减小1.9°。下颌Spee氏曲线与上颌补偿曲线明显整平。结论:应用方丝弓矫治技术拔牙治疗方法可以有效矫治恒牙期骨性安氏II类1分类错,其改善的关键在于上切牙内收前深覆的矫治。     

应用多曲方丝弓技术矫治成人前牙重度深覆(牙合)

目的 探讨多曲方丝弓技术在治疗成人前牙重度深覆(牙合)中的作用.方法 选择20例成人前牙重度深覆(牙合)患者,使用多曲方丝弓矫治深覆(牙合).治疗前后拍摄X线头颅侧位定位片,并进行X线头影测量分析.结果 U1A-PP平均减小了1.75 mm,L1A-MP平均减小了1.67 mm,U6-PP平均增加了1.53 mm,L6-MP平均增加了1.53 mm,说明多曲方丝弓能压低前牙,升高后牙.结论 应用多曲方丝弓技术,能压低前牙,升高后牙,对于成人前牙重度深覆(牙合)是一种快速、有效整平牙弓的方法 .     

10～15岁骨性Ⅲ类错双期矫治前后的软组织变化研究

目的:探讨一种适合较大年龄骨性III类错的新型矫治方法并评价对软组织改变的效果及其机制。方法:选取30例10～15岁骨性III类错患者,将治疗分为两个阶段,第一阶段给予上颌前方牵引配合快速扩弓进行治疗,约半年后开始第二阶段多曲方丝弓技术直至咬合关系达到理想状态,给予保持。结果:所有患者经双期矫治后,上颌骨及上切牙前移,使面中部及上唇前移,下颌骨及下切牙后退,使颏部及下唇后移。从根本上改变了骨性III类错患者的凹陷型侧貌。结论:前方牵引可使骨改建,多曲方丝弓技术可产生充分牙性代偿,取二者之长将其相结合矫治骨性III类错,使其凹陷型侧貌由凹变直或变凸,显著改善了此类患者的容貌。是一种疗程短、效果佳、费用低的矫治方法,值得临床推广。     

多曲方丝弓与直丝弓治疗安氏Ⅱ类Ⅰ分类错牙合畸形患者疗效比较

目的 比较多曲方丝弓与直丝弓矫治技术在Ⅱ类Ⅰ分类错牙合非拔牙病例的矫治效果.方法选取36例安氏Ⅱ类Ⅰ分类错牙合病例,中度拥挤覆盖,随机分成多曲方丝弓组和直丝弓组进行矫治.两组均在治疗前后进行头影测量,对SNA（o）、SNB（o）、ANB（o）、U1-SN（o）、L1-MP（o）、U1-L1（o）、MP-SN（o）、U1-X（mm）、U1-Y（mm）、L1-X（mm）、L1-Y（mm）、OB（mm）进行记录,将治疗前后效果对比及组间比较采用t检验.结果 36例患者经治疗前牙覆牙合覆盖达到正常,磨牙呈中性关系,后牙咬合紧密,面型没有出现前突.治疗后两组均有效,尤以多曲方丝弓组为优.治疗后多曲方丝弓组U1-Y、U1-SN、U1-L1测量指标均有改善,其变化具有统计学意义（P＜0.05）,SNA、SNB、MP-SN、L1-Y等指标改变不明显.多曲方丝弓组与直丝弓组U1-SN、U1-Y、OB比较,多曲方丝弓组疗效优于直丝弓组,差异有统计学意义（P＜0.05）.多曲方丝弓组治疗时间为18~23个月,平均（21.7±2.6）个月;直丝弓组治疗时间为22~28个月平均（26.1±2.8）个月.差异有统计学意义（P＜0.05）.结论对于安氏Ⅱ类Ⅰ分类患者2种方法治疗均得到了改善,多曲方丝弓组较直丝弓组病例改善更为明显,更有效地矫正上颌前突、前牙开牙合,纠正上唇紧张外翻,协调上下唇软组织关系,改善面型.     

改良片段弓技术压低上前牙对深覆矫治效果的临床观察

目的:探讨改良片段弓技术压低上前牙对深覆矫治的临床疗效及其作用机制。方法:选择15例前牙深覆患者,采用直丝固定矫治器结合改良片段弓技术打开其咬合,通过X线头影测量分析患者矫治前、后前牙深覆的改变情况,评价其治疗效果。结果:患者治疗后上前牙获得垂直向压入,前牙咬合打开,深覆得到矫治,后牙垂直向及矢状向无明显变化。结论:改良片段弓技术能压低前牙段,同时控制后牙段的伸长,有利于深覆特别是高角、露龈笑或成年深覆患者的矫治;其压低辅弓适宜的初始加载力值为50g左右。     

MEAW技术治疗平面偏斜机制的有限元研究

目的:对应用多曲方丝弓技术纠正平面偏斜时的力学系统进行有限元分析,了解多曲方丝弓加力后牙齿及牙周支持组织的应力分布的情况。方法:建立多曲方丝弓、上颌牙列及牙周支持组织的有限元模型,然后进一步模拟临床加力方法,在两侧弓丝"L"曲水平部位分别加载方向相反的垂直方向的控制位移(0.5mm、1.0mm、1.5mm、2.0mm),然后进行非线性分析。结果:MEAW弓丝经调整加力后,在相应牙齿的托槽位置会产生UY方向的集中力,并且两侧的集中力方向相反;弓丝整体应力分布比较均匀,没有出现较大的应力集中现象。结论:①本研究建立的多曲方丝弓、上颌牙列及牙周支持组织的三维有限元模型,比较符合实际情况,可适用于多曲方丝弓矫治技术的研究;②应用多曲方丝弓技术纠正平面偏斜时,弓丝整体无较大的应力集中点,同时牙周膜的应力分布也比较均匀,利于牙齿的整体移动。     

多曲方丝弓在前牙开合畸形矫治中的应用效果

目的 分析矫治前牙开合畸形应用多曲方丝弓技术的临床效果。方法 选择2022年3月-2023年3月 我院收治的80例前牙开合畸形患者作为研究对象,按照随机数字表法分为对照组和试验组,各40例。对照 组应用常规矫治措施,试验组应用多曲方丝弓技术治疗,比较两组SNA角度值、治疗满意度、牙齿功能评 分。结果 试验组治疗后SNA角为（76.47±0.23）°,小于对照组的（79.84±0.34）°（P＜0.05）;试验组 治疗满意率为95.00%,高于对照组的80.00%（P ＜0.05）;试验组美观评分、咀嚼能力评分以及咬合力评分 均优于对照组（P ＜0.05）。结论 前牙开合畸形应用多曲方丝弓技术进行矫治,能够改善SNA角度,提高 治疗满意度,改善牙齿美观评分、咀嚼能力评分以及咬合力评分,值得应用。     

Vasopressor hormone response following mesenteric traction during major abdominal surgery

Background : We investigated the vasopressor hormone response following mesenteric traction (MT) with hypotension due to prostacyclin (PGI₂) release in patients undergoing abdominal surgery with a combined general and epidural anesthesia. Methods : In a prospective, randomized, placebo-controlled study we administered 400 mg ibuprofen (i.v.) in 42 patients scheduled for abdominal surgery. General anesthesia was combined with epidural anesthesia (T4-L1). Before as well as 5, 15, 30, 45, and 90 min after MT we recorded plasma osmolality, hemodynamics and measured 6-keto-PGFlα (stabile metabolite of PGI₂), TXB₂ (stabile metabolite of thromboxane A₂) active renin, and arginine vasopressin (AVP) plasma concentrations by radioimmunoassay. Catecholamine levels were assessed by high-pressure liquid chromatography (HPLC) with electrochemical detection. Results : Following MT, arterial hypotension occurred along with a substantial PGI₂ release. This was completely abolished by ibuprofen administration. Although plasma levels of 6-keto-PGF_1α (1133 (708) vs. 60 (3) ng/L, median (median absolute deviation), P=0.0001, placebo vs. ibuprofen) remained significantly elevated, blood pressure was restored within 30 min after MT in the placebo group. At the same point in time plasma concentrations of TXB² (164 (87) vs. 58 (1) ng/L, P=0.0001), epinephrine (46 (33) vs. 14 (6) ng/L, P=0.001), AVP (41 ± (18) vs. 12 (7) ng/L, P=0.0004), and active renin (27 (12) vs. 12 (4) ng/L, P = 0.001) were significantly higher in placebo-treated patients. Conclusion : Under combined general and epidural anesthesia arterial hypotension following MT due to endogenous PGI₂ release is associated with enhanced release of AVP, active renin, epinephrine and thromboxane A₂, presumably contributing to hemodynamic stability within 30 min after MT.     

A Teaspoon Pump for Pumping Blood with High Hydraulic Efficiency and Low Hemolysis Potential

Abstract: Virtually all blood pumps contain some kind of rubbing, sliding, closely moving machinery surfaces that are exposed to the blood being pumped. These valves, internal bearings, magnetic bearing position sensors, and shaft seals cause most of the problems with blood pumps. The original teaspoon pump design prevented the rubbing, sliding machinery surfaces from contacting the blood. However, the hydraulic efficiency was low because the blood was able to "slip around" the rotating impeller so that the blood itself never rotated fast enough to develop adequate pressure. An improved teaspoon blood pump has been designed and tested and has shown acceptable hydraulic performance and low hemolysis potential. The new pump uses a nonrotating "swinging" hose as the pump impeller. The fluid enters the pump through the center of the swinging hose; therefore, there can be no fluid slip between the revolving blood and the revolving impeller. The new pump uses an impeller that is comparable to a flexible garden hose. If the free end of the hose were swung around in a circle like half of a jump rope, the fluid inside the hose would rotate and develop pressure even though the hose impeller itself did not "rotate"; therefore, no rotating shaft seal or internal bearings are required.     

Microspheres Based Detoxification System: A New Method in Convective Blood Purification

Abstract: A variety of protein-bound or hydrophobic substances, accumulating as a result of pathologic conditions such as exogenous or endogenous intoxications, are removed poorly by conventional detoxification methods because of low accessibility (hemodialysis), insufficient adsorption capabilities (hemosorption), low efficiency (peritoneal dialysis), or economic limitations (high-volume plasmapheresis). Combining advantages of existing methods with microspheric technology, a module-based system was designed. Major operating parameters of the latter can be modified to allow for adjustment to individual clinical situations. An extracorporeal blood circuit including a plasmafilter is combined with a secondary high-velocity plasma circuit driven by a centrifugal pump. Different microspheric adsorbers can be combined in one circuit or applied in sequence. Thus, a prolonged treatment can be tailored using specially designed selective adsorber materials. Comparing this system with existing methods (high-flux hemodialysis, molecular adsorbent recycling system), results from our in vitro studies and animal experiments demonstrate the superior efficiency of substance removal.     

A comparison of the inhibitory effects of four volatile anaesthetics on the metabolism of chlorzoxazone, a substrate for CYP2E1, in rabbits

Background: Halothane inhibits in vitro and in vivo activity of cytochrome P-450 (CYP) 2E1. There are several fluorinated volatile anaesthetics besides halothane, and most of them are defluorinated by CYP2E1. It is unclear whether other fluorinated anaesthetics inhibit the in vivo activity of CYP2E1.
Methods: We compared the inhibitory effects of therapeutic concentrations of four inhalational anaesthetics, halothane, enflurane, isoflurane, and sevoflurane, on chlorzoxazone metabolism in rabbits receiving artificial ventilation.
Results: All four inhalational anaesthetics decreased arterial blood pressure and increased plasma chlorzoxazone concentration. However, no significant differences in the plasma chlorzoxazone concentration were found between the four anaesthetics. The estimated chlorzoxazone clearance increased after beginning inhalation with all four agents, but no significant difference in clearance was noted between agents.
Conclusions: At therapeutic concentrations, the in vivo inhibitory effect on chlorzoxazone metabolism was similar for all four inhalational anaesthetics examined, even though their chemical characteristics and extent of hepatic metabolism differ considerably.     

Tissue perfusion in relation to cardiac output during continuous positive-pressure ventilation and administration of propranolol or verapamil

Background : Our objective was to determine whether administration of propranolol or verapamil modifies the hemodynamic adaptation to continuous positive-pressure ventilation (CPPV), in particular the regional distribution of cardiac output (CO).
Methods : General hemodynamics and regional blood flows assessed by microsphere technique (15 (μm) were recorded in 16 anesthetized pigs during spontaneous breathing (SB) and CPPV with 8 cm H₂O end-expiratory pressure (CPPV8) before and after intravenous administration of propranolol (0.3 mg · kg⁻¹ followed by 0.15 mg · kg⁻¹ · h⁻¹, n=8) or verapamil (0.1 mg · kg⁻¹ followed by 0.3 mg · kg⁻¹ · h⁻¹, n=8).
Results : CPPV8 depressed CO by 25% without shifts in its relative distribution with the exception of a noteworthy increase in adrenal perfusion. Propranolol increased arterial blood pressure, and due to a fall in heart rate, CO dropped by 25%. The kidneys and, to a lesser extent, the splanchic region and central nervous system received increased fractions of the remaining CO at the expense of skeletal muscle flow. Similar patterns were seen during SB and CPPV8 such that the combination of propranolol and CPPV8 depressed CO by 50%. The circulatory effects of verapamil were less evident but myocardial perfusion tended to increase.
Conclusions : The combination of propranolol or verapamil with CPPV does not result in any specific hemodynamic interaction in anesthetized pigs, except that the combined effect of propranolol and CPPV may severely reduce CO.     

Bariatric Surgery in Some "Central and East-European (former Eastern bloc)"Countries - Current Status and Prediction for the Next Millennium

Background: Obesity is increasing globallly, including in the formerly "Eastern Bloc" countries. Methods: A survey was made of obesity and bariatric surgery. Results: In the 8 East and Central European countries studied, with total population 300 million, roughly 43% of the population was overweight (BMI 25-30), 23% obese (BMI > 30), with about 15 million people morbidly obese (BMI > 40). From 0-10 morbidly obese individuals/100,000/year undergo bariatric surgery. Conclusion: Most countries were found to provide inadequate treatment for obesity.The majority of the morbidly obese are not treated effectively. However, health-care awareness of obesity and bariatric surgeons are slowly increasing.     

Volatile anaesthetics reduce adhesion of blood platelets under low-flow conditions in the coronary system of isolated guinea pig hearts

Background : Inhibitory effects of volatile anaesthetics on platelet aggregation have been demonstrated in several studies. However, the influence of volatile anaesthetics on intracoronary platelet adhesion has not been elucidated so far.
Methods : Isolated hearts of guinea pigs were perfused with buffer in the absence or presence of volatile anaesthetics (0.5 and 1 MAC) at constant coronary flow rates of 5 ml/min for 25 min, then 1 ml/min for 30 min and again 5 ml/min for 10 min. Before, during and after low-flow perfusion, a bolus of human platelets was applied into the coronary system. To simulate thrombogenic conditions, 0.3 U/ml human thrombin was infused during low-flow perfusion and reperfusion. The number of platelets sequestered to the endothelium was calculated from the difference between coronary in- and output of platelets. The myocardial production of lactate and consumption of pyruvate and coronary perfusion pressure were also determined.
Results : At a flow rate of 5 ml/min only about 3% of the applied platelets did not emerge from the coronary system, in any group. In contrast, 13.1±1.2% (mean±SEM) of infused platelets became adherent in low-flow perfusion in the control group without anaesthetic. The adherence was reduced with each 1 MAC isoflurane (to 6.2±1.2%), sevoflurane (to 4.4±0.9%) or halothane (to 3.2±1.5%) (each P <0.05 vs. control). Volatile anaesthetic, 0.5 MAC, did not inhibit platelet adhesion to a statistically significant extent in any case. Perfusion pressure and metabolic parameters were not statistically different between the control and the hearts exposed to anaesthetics.
Conclusion : Volatile anaesthetics in a concentration of 1 MAC can reduce the adhesion of platelets in the coronary system under reduced flow conditions. This action does not arise from vasodilation or inhibition of ischaemic stress.     

Synergistic interaction between the effects of propofol and midazolam with fentanyl on phrenic nerve activity in rabbits

Background: It has been shown that the depressive effects of both propofol and midazolam on consciousness are synergistic with opioids, but the nature of their interactions on other physiological systems, e. g. respiration, has not been fully investigated. The present study examined the effect of propofol and midazolam alone and in combination with fentanyl on phrenic nerve activity (PNA) and whether such interactions are additive or synergistic. Methods: PNA was recorded in 27 anaesthetised and artificially ventilated rabbits. In three groups, propofol, fentanyl and midazolam were administered intravenously in incremental doses to construct dose-response curves for the depressant effects of each one on PNA. In another two groups, the effect of pretreatment with either fentanyl 1 μg · kg^?1 i. v. or midazolam 0.05 mg · kg^?1 i. v. on the effects of propofol and fentanyl respectively on PNA were studied. Results: Propofol and fentanyl caused a dose-dependent depression of PNA with complete abolition at the highest total doses of 16 mg · kg^?1 i. v. and 32 μg · kg^?1 i. v., respectively. In contrast, midazolam in incremental doses to a total of 0.8 mg · kg^?1 reduced mean PNA by 63%, but approximately 12% of PNA remained at a total dose as high as 6.4 mg · kg^?1. The mean ED₅₀s, calculated from dose-response curves, were 5.4 mg · kg^?1, 3.9 μg · kg^?1 and 0.4 mg · kg^?1 for propofol, fentanyl and midazolam, respectively. Initial doses of either fentanyl 1 μg · kg^?1 i. v. or midazolam 0.05 mg · kg^?1 i. v. acted synergistically with subsequent doses of either propofol or fentanyl to abolish PNA at total doses of 8 mg · kg^?1 and 8 μg · kg^?1, respectively. Conclusion: Fentanyl has a synergistic interaction with both propofol and midazolam on PNA and hence potentially on respiration.     

Influence of dopexamine hydrochloride on haemodynamics and regulators of circulation in patients undergoing major abdominal surgery

Background: Catecholaminergic support is often used to improve haemodynamics in patients undergoing major abdominal surgery. Dopexamine is a synthetic vasoactive catecholamine with beneficial microcirculatory properties. Methods: The influence of perioperative administration of dopexamine on cardiorespiratory data and important regulators of macro- and microcirculation were studied in 30 patients undergoing Whipple pancreaticduodenectomy. The patients received randomized and blinded either 2 μg · kg^?1 · min^?1 of dopexamine (n=15) or placebo (n=15, control group). The infusion was started after induction of anaesthesia and continued until the morning of the first postoperative day. Endothelin-1 (ET-1), vasopressin, atrial natriuretic peptide (ANP), and catecholamine plasma levels were measured from arterial blood samples. Measurements were carried out after induction of anaesthesia, 2 h after onset of surgery, at the end of surgery, 2 h after surgery, and on the morning of the first postoperative day. Results: Cardiac index (CI) increased significantly in the dopexamine group (from 2.61±0.41 to 4.57±0.78 1 · min^?1 · m^?2) and remained elevated until the morning of the first postoperative day. Oxygen delivery index (DO₂I) and oxygen consumption index (VO₂I) were also significantly increased in the dopexamine group (DO₂I: from 416±91 to 717±110 ml/m² · m²; VO₂I: from 98±25 to 157±22 ml/m² · m²), being significantly higher than in the control group. pHi remained stable only in the dopexamine patients, indicating adequate splanchnic perfusion. Vasopressive regulators of circulation increased significantly only in the untreated control patients (vasopressin: from 4.37±1.1 to 35.9±12.1 pg/ml; ET-1: from 2.88±0.91 to 6.91±1.20 pg/ml). Conclusion: Patients undergoing major abdominal surgery may profit from prophylactic perioperative administration of dopexamine hydrochloride in the form of improved haemodynamics and oxygenation as well as beneficial influence on important regulators of organ blood flow.     

Systemic analgesia adapted to the children's condition

A concept of balanced analgesia using nonsteroidal anti-inflammatory drugs (NSAIDs), paracetamol (acetaminophen), opioids, and corticosteroids can also be used in patients with pre-existing illnesses. NSAIDs are the most effective treatment for acute pain of moderate intensity in children; however, these drugs should be avoided in patients at increased risk for serious side effects, e.g. patients with renal impairment, bleeding tendency, or extreme prematurity. NSAIDs can be given with minimal risks to the younger child with mild to moderate asthma, and, in these patients, the use of steroids can be encouraged; in addition to their antiemetic and analgesic action, a beneficial effect on asthma symptoms can be expected. In the non-intubated child with cerebral trauma, exaggerated sedation caused by opioids and increased bleeding tendency caused by NSAIDs must be avoided. In neonates and small infants, the oral administration of sucrose or glucose is helpful to minimize pain reaction during short uncomfortable interventions.