Intracardiac Shunt—Use of the Hydrogen-Sensitive Catheter to Clarify False Positive Diagnosis of Left-to-Right Shunt

The charts of 142 patients who had diagnostic right heart catheterization with conventional oximetry, oxygen content determinations and hydrogen electrode curve recording for left-to-right shunt were reviewed. A false positive diagnosis of surgical significance would have been made in nine patients if the hydrogen electrode had not been used. In addition, a diagnosis of left-to-right shunt could have been made at the wrong chamber level in three additional cases.     

CORRECTION OF ANOMALOUS VENOUS RETURN FROM THE RIGHT LUNG TO THE INFERIOR VENA CAVA (SCIMITAR DEFORMITY)

Anomalous pulmonary venous drainage to the inferior vena cava is a rare congenital cardiac defect. Oxygenated blood from the right lung enters the right atrium resulting in a left-to-right shunt. Because the radiographic shadow of the anomalous vein resembles a curved saber, this defect has been called the "scimitar" deformity. From 1958 through June 30, 1975, 11 patients underwent surgical correction of this anomaly at our institution with 10 survivors. Diagnosis was made by routine roentgenography of the chest in all but one patient. Eight patients had total correction which consisted of implanting the anomalous vein into the right atrium, opening the interatrial septum and applying a patch graft as a baffle to direct pulmonary venous blood into the left atrium. Five patients had associated cardiac defects which were also repaired. Three patients underwent pneumonectomy and all survived. The only operative death occurred in a 5-year-old female with an atrial septal defect and endocardial cushion defect. We believe the existence of a large left-to-right shunt justifies surgical intervention. The prognosis appears to depend upon the presence of other cardiac or pulmonary anomalies.     

Immunosensor for the diagnosis of Chagas' disease

Trypanosoma cruzi proteins from epimastigote membranes, herein referred as antigens, have been used for the construction of an amperometric immunosensor for serological diagnosis of Chagas' disease. The proteins used had a molecular mass ranging from 30 to 100 kDa. The gold electrode was treated with cysteamine and glutaraldehyde prior to antigen immobilization. Antibodies present in the serum of patients with Chagas' disease were captured by the immobilized antigens and the affinity interaction was monitored by chronoamperometry at a potential of -400 mV (versus Ag pseudo-reference electrode) using peroxidase-labeled IgG conjugate and hydrogen peroxide, iodide substrate. The incubation time to allow maximum antigen-antibody and antibody-peroxidase-labeled IgG interactions was 20 min with a reactivity threshold at -0.104 microA.     

Continuous in vivo measurement of arterial PO2 in humans.

A system suitable for prolonged continuous in vivo measurement of human arterial PO2 is described. The system uses a polarographic electrode developed by Kimmich and Kreuzer, inserted in a specially made shunt between the radial artery and an antecubital vein. Nhe electrode surface is maintained in a fixed position parallel to the flow of blood; blood velocity dependency is small owing to the high flow rate achieved (more than 40 cm/s); clotting is prevented by the material used and the continuous instillation of heparin through the arterial end of the shunt. The system has been tested in vitro; it is stable (variation less than 0.5% in 24 h), linear and precise (plus or minus 0.2%) in a broad range of PO2 values (from about 10 mmHg to more than 700 mmHg); its response time is 0.4 s per 95% of deflection. It has been applied to 35 patients for periods ranging between 6 and 24 h; most of the patients were ventilated by an Engstrom respirator.     

Neonatal Cardiac Distress—A Practical Approach to Recognition,Diagnosis, and Management

The death rate among neonates with cardiovascular disease is 50 percent during the first six months, with the majority dying during the first month. With early diagnosis most of these babies could be saved. In approaching the diagnosis of cardiac distress in the newborn, it is important to remember that the types of cardiovascular disease which cause symptoms and death early in life are quite different from those in older children. Lesions such as hypoplasia of the left heart, transposition of the great arteries, endocardial fibroelastosis, pulmonary atresia, mitral atresia, tricuspid atresia and truncus arteriosus are common, not rare, causes of cardiac distress in the newborn.A classification of neonatal cardiovascular diseases into seven pathophysiological groups is presented as a basis for an effective, practical approach to the differential diagnosis of the potentially lethal lesions. This approach is simplified further since over 90 percent of babies with cardiac distress have one of three lesions: (1) Large left-to-right shunt (characterized by the presence of massive plethora on the chest roentgenogram), (2) Large right-to-left shunt (association with intense cyanosis) or (3) Severe obstruction (including hypoplasia of the left heart, which is the most common cause of death due to cardiac distress during the first week of life).     

Microsphere studies of bullfrog central vascular shunts during diving and breathing in air.

Bidirectional central vascular shunts were measured during diving and breathing in air in unanesthetized bullfrogs by using pulmonary trapping of 38 mu mean diameter radionuclide-labelled microspheres. Six animals studied during diving exhibited a strong overall right-to-left shunting pattern comprised of both a predominant (68% mean) right-to-left shunt and a weak (23%) left-to-right countershunt. Five animals with access to air showed a variety of distribution patterns, including predominant shunts in the left-to-right (1 animal) and right-to-left (1 animal) directions, nearly complete mixing (2 animals) and separation of systemic and pulmonary venous returns (1 animal).     

Lactate kinetics at rest and during exercise in lambs with aortopulmonary shunts.

In a previous study [G. C. M. Beaufort-Krol, J. Takens, M. C. Molenkamp, G. B. Smid, J. J. Meuzelaar, W. G. Zijlstra, and J. R. G. Kuipers. Am. J. Physiol. 275 (Heart Circ. Physiol. 44): H1503-H1512, 1998], a lower systemic O2 supply was found in lambs with aortopulmonary left-to-right shunts. To determine whether the lower systemic O2 supply results in increased anaerobic metabolism, we used [1-13C]lactate to investigate lactate kinetics in eight 7-wk-old lambs with shunts and eight control lambs, at rest and during moderate exercise [treadmill; 50% of peak O2 consumption (VO2)]. The mean left-to-right shunt fraction in the shunt lambs was 55 +/- 3% of pulmonary blood flow. Arterial lactate concentrations and the rate of appearance (Ra) and disappearance (Rd) of lactate were similar in shunt and control lambs, both at rest (lactate: 1, 201 +/- 76 vs. 1,214 +/- 151 micromol/l; Ra = Rd: 12.97 +/- 1.71 vs. 12.55 +/- 1.25 micromol. min-1. kg-1) and during a similar relative workload. We found a positive correlation between Ra and systemic blood flow, O2 supply, and VO2 in both groups of lambs. In conclusion, shunt lambs have similar lactate kinetics as do control lambs, both at rest and during moderate exercise at a similar fraction of their peak VO2, despite a lower systemic O2 supply.     

Amperometric biosensor for the detection of hydrogen peroxide using catalase modified electrodes in polyacrylamide

A simple biosensor for the detection of hydrogen peroxide in organic solvents has been developed and coupled to a flow injection analysis (FIA) system. Catalase was entrapped in polyacrylamide gel and placed on the surface of platinum (working electrode) fixed in a Teflon holder with Ag-wire (auxiliary electrode), followed by addition of filter paper soaked in KCl. The entrapped catalase gel was held on the electrode using membranes. The effects of cellulose and polytetrafluroethylene (PTFE) membranes on the electrode response towards hydrogen peroxide have been studied. The modified electrode has been used to study the detection of hydrogen peroxide in solvents like water, dimethyl sulfoxide (DMSO), and 1,4-dioxane using amperometric techniques like cyclic voltammetry (CV) and FIA. The CV of modified catalase electrode showed a broad oxidation peak at -150 mV and a clear reduction peak at -212 mV in the presence of hydrogen peroxide. Comparison of CV with hydrogen peroxide in various solvents has been carried out. The electrode showed an irreversible kinetics with DMSO as the solvent. A flow cell has been designed in order to carry on FIA studies to obtain calibration plots for hydrogen peroxide with the modified electrode. The calibration plots in several solvents such as water, dimethyl sulfoxide, 1,4-dioxane have been obtained. The throughput of the enzyme electrode was 10 injections per hour. Due to the presence of membrane the response time of the electrode is concentration dependent.     

A GLASS ELECTRODE APPARATUS FOR MEASURING THE pH VALUES OF VERY SMALL VOLUMES OF SOLUTION

A glass electrode apparatus is described with which pH measurements can be made with as small volumes as 2 drops (about 0.14 cc.) of solution. Using this apparatus the change of pH of the vacuolar sap of Nitella, due to the penetration of brilliant cresyl blue, has been readily followed. The sap and the dye have been found to poison the usual type of hydrogen electrode.     

Mesentericocaval “Jump” Graft in Management of Portal Hypertension: Experience with 24 Cases

A series of 24 patients with cirrhosis have undergone mesentericocaval shunt operations for the relief of portal hypertension. Overall the results have been satisfactory. Four of the five patients treated as an emergency and 17 of the 19 who had the operation two to six weeks after haemorrhage had been controlled left hospital alive and well. Separation of the patients into three categories according to the findings of clinical and biochemical tests, however, showed that subsequent survival was satisfactory for patients in categories A and B but that all four patients in category C had died within one year after surgery. Assessment at three months showed that in three patients moderate hepatic encephalopathy had developed.Evidence that the shunt remains patent was shown by a low incidence of repeated gastrointestinal haemorrhage and a marked diminution in variceal size in 18 of the 19 cases examined serially. Radiographic techniques for confirming shunt patency were compared and cannulation of the graft via the femoral vein was found to provide a reliable and rapid means of assessment.     

对比增强经颅多谱勒超声对心房右向左分流患者的诊断价值的分析

目的:比较对比增强经颅多普勒超声与经胸壁超声心动图、经食管超声心动图对心房右→左分流患者的鉴别诊断价值。方法:回顾性分析2014年9月至2018年11月哈尔滨医科大学附属第一医院经手术证实的41例心房右→左分流患者对比增强经颅多普勒超声及经胸壁超声心动图的检查所见及诊断结果,并回顾性分析其中29例患者对比增强经颅多普勒超声、经胸壁超声心动图及经食管超声心动图的检查所见及诊断结果。结果:在经手术证实的41例心房右→左分流患者中,对比增强经颅多普勒超声检查阳性结果 41例,阴性结果 0例,诊断准确性为100%;经胸壁超声心动图检查阳性结果 20例,阴性结果 21例,诊断准确性为48.8%。其中,同时进行对比增强经颅多普勒超声、经胸壁超声心动图及经食管超声心动图检查的29例患者中,经胸壁超声心动图阳性结果 12例,阴性结果 17例,诊断准确性为41.4%;经食管超声心动图检查阳性结果 24例,阴性结果 5例,诊断准确性为82.8%。结论:对比增强经颅多普勒超声可提高心房右→左分流的诊断准确率,其与经胸壁超声心动图及经食管超声心动图结合应用可提高心房右→左分流的鉴别诊断能力。     

Maximal exercise capacity and oxygen consumption of lambs with an aortopulmonary left-to-right shunt

We determined maximal exercise capacity and measured hemodynamics in 10 6-wk-old lambs with an aortopulmonary left-to-right shunt [S, 57 +/- 11%, (SD)] and in 9 control lambs (C) during a graded treadmill test 8 days after surgery. Maximal exercise capacity (3.7 +/- 0.2 km/h and 10 +/- 5% inclination vs. 4.0 +/- 0.9 km/h and 15 +/- 0% inclination, P less than 0.02) and peak oxygen consumption (25 +/- 7 vs. 34 +/- 8 ml O2.min-1.kg-1, P less than 0.02) were both lower in the shunt than in the control lambs. This was due to a lower maximal systemic blood flow in the shunt lambs (271 +/- 38 vs. 359 +/- 71 ml.min-1.kg-1, P less than 0.01). Despite their high maximal left ventricular output, which was higher than in the control lambs (448 +/- 87 vs. 359 +/- 71 ml.min-1.kg-1, P less than 0.05), the left-to-right shunt could not be compensated for during maximal exercise because of a decreased reserve in heart rate (S: 183 +/- 22 to 277 +/- 38 beats/min; C: 136 +/- 25 to 287 +/- 29 beats/min) and in left ventricular stroke volume (S: 1.8 +/- 0.3 to 1.6 +/- 0.4 ml/kg; C: 1.0 +/- 0.3 to 1.3 +/- 0.2 ml/kg). We conclude that exercise capacity of shunt lambs is lower than that of control lambs, despite a good left ventricular performance, because a part of the reserves for increasing the left ventricular output is already utilized at rest.     

Age at time of first intercourse v. chronologic age as a basis for Pap smear screening.

The Walton Report on cervical cancer screening programs recently recommended a new program for screening for cervical cancer based on chronologic age, calling for 3- and 5-year intervals between examinations. It recommended that such examinations be discontinued after 60 years of age. In a group of 232 routinely examined women (aged 18 to 47 years) in whom cervical intraepithelial neoplasia developed the timing of onset of the disease and the implications for screening were studied. The average age at the time of diagnosis was 30 years; in 20% of the patients the diagnosis had been made after age 35. The screening program recommended in the Walton Report would have been effective in diagnosing most cases (80%) in this sample by age 35 and all by age 60. However, when the patients were grouped according to age at the time of first intercourse, the diagnosis had been made after age 35 in only 13% of those who started having intercourse at age 15 to 17 years, 20% of those who started at age 18 to 19 years and 33% of those who started at age 20 years of later. When the times of diagnosis were expressed by number of years of intercourse the distributions became uniform in the same three groups; in 72% of all the patients the diagnosis had been made within the first 15 years of intercourse, in 88% it had been made within 20 years and in 100% it had been made by 30 years. These data suggest that a program based on number of years of intercourse may be more uniform and more efficient than one based on chronologic age, and that cytologic examinations should be concentrated during the time when most cases develop -- 6 to 20 years after the time of first intercourse.     

High hydrogen production rate of microbial electrolysis cell (MEC) with reduced electrode spacing

Practical applications of microbial electrolysis cells (MECs) require high hydrogen production rates and a compact reactor. These goals can be achieved by reducing electrode spacing but high surface area anodes are needed. The brush anode MEC with electrode spacing of 2 cm had a higher hydrogen production rate and energy efficiency than an MEC with a flat cathode and a 1-cm electrode spacing. The maximum hydrogen production rate with a 2 cm electrode spacing was 17.8 m(3)/m(3)d at an applied voltage of E(ap)=1 V. Reducing electrode spacing increased hydrogen production rates at the lower applied voltages, but not at the higher (>0.6 V) applied voltages. These results demonstrate that reducing electrode spacing can increase hydrogen production rate, but that the closest electrode spacing do not necessarily produce the highest possible hydrogen production rates.     

Atrial septostomy benefits severe pulmonary hypertension patients by increase of left ventricular preload reserve

At present, it is unknown why patients suffering from severe pulmonary hypertension (PH) benefit from atrial septostomy (AS). Suggested mechanisms include enhanced filling of the left ventricle, reduction of right ventricular preload, increased oxygen availability in the peripheral tissue, or a combination. A multiscale computational model of the cardiovascular system was used to assess the effects of AS in PH. Our model simulates beat-to-beat dynamics of the four cardiac chambers with valves and the systemic and pulmonary circulations, including an atrial septal defect (ASD). Oxygen saturation was computed for each model compartment. The acute effect of AS on systemic flow and oxygen delivery in PH was assessed by a series of simulations with combinations of different ASD diameters, pulmonary flows, and degrees of PH. In addition, blood pressures at rest and during exercise were compared between circulations with PH before and after AS. If PH did not result in a right atrial pressure exceeding the left one, AS caused a left-to-right shunt flow that resulted in decreased oxygenation and a further increase of right ventricular pump load. Only in the case of severe PH a right-to-left shunt flow occurred during exercise, which improved left ventricular preload reserve and maintained blood pressure but did not improve oxygenation. AS only improves symptoms of right heart failure in patients with severe PH if net right-to-left shunt flow occurs during exercise. This flow enhances left ventricular filling, allows blood pressure maintenance, but does not increase oxygen availability in the peripheral tissue.     

Atrial Septal Defect in Infancy

The case histories of seven infants with atrial septal defect are presented to draw attention to certain features and possible dangers of this defect in infancy. Four infants were asymptomatic but one failed to thrive and two died suddenly. Five had ejection murmurs and two, with pulmonary hypertension, had loud pan-systolic murmurs with a thrill. In two infants murmurs were noted at birth, but in five they were first heard between the ages of 1 and 6 months. The second pulmonary sound was initially narrowly split in all, but became widely split between the ages of 12 and 20 months. Electrocardiograms and chest roentgenograms were of little help at the outset but later showed findings characteristic of the defect after one year. All infants were catheterized; a left-to-right atrial shunt was detected in each instance. Pulmonary hypertension was present in two infants, one of whom died.     

脑室—腹腔分流术后感染26例诊治分析

目的探讨脑室—腹腔分流术后感染的早期诊断和治疗原则。方法回顾性分析26例脑室—腹腔分流术后感染病例的诊断和治疗办法,所有病例均进行血液和脑脊液的培养及影像学检查。结果 2例死于感染并发症,2例感染复发,21例患者重新安装分流装置,3例病情较轻的患者经分流泵及鞘内给药后痊愈。结论脑室—腹腔分流术后的早期诊断非常重要,一些非特异性的症状和体征需引起重视。对于感染的病例,及时移除分流装置,同时行脑室外引流冲洗和脑室内注药,当脑脊液达到无菌状态后重新植入分流装置是行之有效的办法。结果表明抗感染应首选万古霉素、第三代头孢菌素或改为美罗培南,待获得培养结果后根据药敏试验针对性用药。脑脊液培养以金黄色葡萄球菌和表皮葡萄球菌多见,经治疗再次培养结果均为阴性。     

The Scimitar Syndrome: Report of Two Cases of Anomalous Venous Return from a Hypoplastic Right Lung to the Inferior Vena Cava

An unusual association of malformations of the right lung was observed in two patients, and 36 similar cases were briefly reviewed. Findings included: (1) anomalous return of the right pulmonary veins, via a common channel, to the inferior vena cava, giving a typical radiological picture; (2) hypoplasia or absence of two major bronchi on the right side; (3) absence of the right pulmonary artery in one patient and hypoplasia in the other; (4) secondary dextroposition of the heart; (5) presence of a left-to-right shunt, through this abnormal circulation, varying from very small in one patient to more than 30% of the pulmonary blood flow in the other. When found together, these anomalies constitute a specific entity, the scimitar syndrome.     

Attachment of gold nanoparticles to glassy carbon electrode and its application for the direct electrochemistry and electrocatalytic behavior of hemoglobin

Gold nanoparticles have been attached onto glassy carbon electrode surface through sulfhydryl-terminated monolayer and characterized by X-ray photoelectron spectroscopy, atomic force microscopy, electrochemical impedance spectroscopy and cyclic voltammetry. The gold nanoparticles-attached glassy carbon electrodes have been applied to the immobilization/adsorption of hemoglobin, with a monolayer surface coverage of about 2.1 x 10(-10) mol cm(-2), and consequently obtained the direct electrochemistry of hemoglobin. Gold nanoparticles, acting as a bridge of electron transfer, can greatly promote the direct electron transfer between hemoglobin and the modified glassy carbon electrode without the aid of any electron mediator. In phosphate buffer solution with pH 6.8, hemoglobin shows a pair of well-defined redox waves with formal potential (E0') of about -0.085 V (versus Ag/AgCl/saturated KCl). The immobilized hemoglobin maintained its biological activity, showing a surface controlled electrode process with the apparent heterogeneous electron transfer rate constant (ks) of 1.05 s(-1) and charge-transfer coefficient (a) of 0.46, and displays the features of a peroxidase in the electrocatalytic reduction of hydrogen peroxide. A potential application of the hemoglobin-immobilized gold nanoparticles modified glassy carbon electrode as a biosensor to monitor hydrogen peroxide has been investigated. The steady-state current response increases linearly with hydrogen peroxide concentration from 2.0 x 10(-6) to 2.4 x 10(-4) M. The detection limit (3sigma) for hydrogen peroxide is 9.1 x 10(-7) M.     

THE IONIZATION OF PROTEIN CHLORIDES

1. By the use of the silver-silver chloride electrode, measurements have been made of the chloride ion concentrations of 1 per cent solutions of five proteins, containing from 0.001 N to 0.1 N hydrochloric acid. The hydrogen ion concentrations of the same solutions have been measured by the use of the hydrogen electrode. 2. The measurements indicate that the chlorides of gelatin, egg albumin, casein, edestin, and serum globulin are highly ionized electrolytes, ionizing to yield chloride ion and a positive protein-hydrogen ion. Their ionization is therefore similar to that of ammonium chloride. 3. The results do not support the idea that a protein chloride does not yield chloride ion on dissociation. They are not in agreement with the idea that the depressing effect of an excess of HCl on the viscosity and other colloidal properties of a protein chloride solution is due to a repression of the ionization of the protein chloride. The results are, however, in complete accord with the theory of colloidal behavior advocated by Loeb.