bluuebunny/crossref_metadata_2025 huggingface dataset:
Improving the representation of peptide‐like inhibitor and antibiotic molecules in the Protein Data Bank
Authors: Dutta Shuchismita , Dimitropoulos Dimitris , Feng Zukang , Persikova Irina , Sen Sanchayita , Shao Chenghua , Westbrook John , Young Jasmine , Zhuravleva Marina A. , Kleywegt Gerard J. , Berman Helen M.
Published: October 2013

With the accumulation of a large number and variety of molecules in the Protein Data Bank (PDB) comes the need on occasion to review and improve their representation. The Worldwide PDB (wwPDB) partners have periodically updated various aspects of structural data representation to improve the integrity and consistency of the archive. The remediation effort described here was focused on improving the representation of peptide‐like inhibitor and antibiotic molecules so that they can be easily identified and analyzed. Peptide‐like inhibitors or antibiotics were identified in over 1000 PDB entries, systematically reviewed and represented either as peptides with polymer sequence or as single components. For the majority of the single‐component molecules, their peptide‐like composition was captured in a new representation, called the subcomponent sequence. A novel concept called “group” was developed for representing complex peptide‐like antibiotics and inhibitors that are composed of multiple polymer and nonpolymer components. In addition, a reference dictionary was developed with detailed information about these peptide‐like molecules to aid in their annotation, identification and analysis. Based on the experience gained in this remediation, guidelines, procedures, and tools were developed to annotate new depositions containing peptide‐like inhibitors and antibiotics accurately and consistently. © 2013 Wiley Periodicals, Inc. Biopolymers 101: 659–668, 2014.
Controlling network topology and mechanical properties of co‐assembling peptide hydrogels
Authors: Boothroyd Stephen , Saiani Alberto , Miller Aline F.
Published: October 2013

Oligopeptides are well‐known to self‐assemble into a wide array of nanostructures including β‐sheet‐rich fibers that when present above a critical concentration become entangled and form self‐supporting hydrogels. The length, quantity, and interactions between fibers influence the mechanical properties of the hydrogel formed and this is typically achieved by varying the peptide concentration, pH, ionic strength, or the addition of a second species or chemical cross‐linking agent. Here, we outline an alternative, facile route to control the mechanical properties of the self‐assembling octa‐peptide, FEFEFKFK (FEKII); simply doping with controlled quantities of its double length peptide, FEFEFKFK‐GG‐FKFKFEFE (FEKII18). The structure and properties of a series of samples were studied here (0–100 M% of FEKII18) using Fourier transform infrared, small angle X‐ray scattering, transmission electron microscopy, and oscillatory rheology. All samples were found to contain elongated, flexible fibers and all mixed samples contained Y‐shaped branch points and parallel fibers which is attributed to the longer peptide self‐assembling within two fibers, thus creating a cross‐link in the network structure. Such behavior was reflected in an increase in the elasticity of the mixed samples with increasing quantity of double peptide. Interestingly the elastic modulus increased up to 30 times the pure FEKII value simply by adding 28 M% of FEKII18. These observations provide an easy, off‐the‐shelf method for an end‐user to control the cross‐linked network structure of the peptide hydrogel, and consequently strength of the hydrogel simply by physically mixing pre‐determined quantities of two similar peptide molecules. © 2013 Wiley Periodicals, Inc. Biopolymers 101: 669–680, 2014.
Expression profiling of cervical cancers in Indian women at different stages to identify gene signatures during progression of the disease
Authors: Thomas Asha , Mahantshetty Umesh , Kannan Sadhana , Deodhar Kedar , Shrivastava Shyam K. , Kumar‐Sinha Chandan , Mulherkar Rita
Published: October 2013

Cervical cancer is the second most common cancer among women worldwide, with developing countries accounting for >80% of the disease burden. Although in the West, active screening has been instrumental in reducing the incidence of cervical cancer, disease management is hampered due to lack of biomarkers for disease progression and defined therapeutic targets. Here we carried out gene expression profiling of 29 cervical cancer tissues from Indian women, spanning International Federation of Gynaecology and Obstetrics (FIGO) stages of the disease from early lesion (IA and IIA) to progressive stages (IIB and IIIA–B), and identified distinct gene expression signatures. Overall, metabolic pathways, pathways in cancer and signaling pathways were found to be significantly upregulated, while focal adhesion, cytokine–cytokine receptor interaction and WNT signaling were downregulated. Additionally, we identified candidate biomarkers of disease progression such as SPP1, proliferating cell nuclear antigen (PCNA), STK17A, and DUSP1 among others that were validated by quantitative real‐time polymerase chain reaction (qRT‐PCR) in the samples used for microarray studies as well in an independent set of 34 additional samples. Integrative analysis of our results with other cervical cancer profiling studies could facilitate the development of multiplex diagnostic markers of cervical cancer progression.
HighRAB25expression is associated with good clinical outcome in patients with locally advanced head and neck squamous cell carcinoma
Authors: Téllez‐Gabriel Marta , Arroyo‐Solera Irene , León Xavier , Gallardo Alberto , López Montserrat , Céspedes Maria V. , Casanova Isolda , López‐Pousa Antonio , Quer Miquel , Mangues Maria A. , Barnadas Agustí , Mangues Ramón , Pavón Miguel A.
Published: October 2013

Currently there are no molecular markers able to predict clinical outcome in locally advanced head and neck squamous cell carcinoma (HNSCC). In a previous microarray study,RAB25was identified as a potential prognostic marker. The aim of this study was to analyze the association betweenRAB25expression and clinical outcome in patients with locally advancedHNSCCtreated with standard therapy. In a retrospective immunohistochemical study (n = 97), we observed thatRAB25‐negative tumors had lower survival (log‐rank,P = 0.01) than patients bearing positive tumors. In an independent prospectivemRNAstudy (n = 117), lowRAB25mRNAexpression was associated with poor prognosis. Using classification and regression tree analysis (CART) we established two groups of patients according to theirRAB25mRNAlevel and their risk of death. LowmRNAlevel was associated with poor local recurrence‐free (log‐rank,P = 0.005), progression‐free (log‐rank,P = 0.002) and cancer‐specific (log‐rank,P < 0.001) survival. Multivariate Cox model analysis showed that low expression ofRAB25was an independent poor prognostic factor for survival (hazard ratio: 3.84, 95% confidence interval: 1.93–7.62,P < 0.001). Patients whose tumors showed highRAB25expression had a low probability of death after treatment. We also found lowerRAB25expression in tumors than in normal tissue (Mann–WhitneyU,P < 0.001). Moreover, overexpression ofRAB25in theUM‐SCC‐74BHNSCCcell line increased cisplatin sensitivity, and reduced cell migration and invasion. Our findings support a tumor suppressor role forRAB25inHNSCCand its potential use to identify locally advanced patients with a high probability of survival after genotoxic treatment.
Cu2O‐Decorated Mesoporous TiO2 Beads as a Highly Efficient Photocatalyst for Hydrogen Production
Authors: Cheng Wei‐Yun , Yu Tsung‐Hsuan , Chao Kang‐Ju , Lu Shih‐Yuan
Published: October 2013

Cu2O‐decorated mesoporous TiO2 beads (MTBs) are developed as a low‐cost, highly efficient photocatalyst for H2 production. MTBs with a high specific surface area of 189 m2 g−1, a large pore volume of 0.43 cm3 g−1 and a suitable pore size of 8.9 nm are decorated with band‐structure‐matched Cu2O nanocrystals through a simple, fast and low‐cost chemical bath deposition process. The Cu2O nanocrystals serve as an electron–hole separation centre to promote H2 evolution. Under optimal operation conditions, an ultra‐high specific H2 evolution rate of 223 mmol h−1 g−1 is achieved. The success is attributed to the structural advantages of the MTBs of high specific surface areas, large pore volumes and suitable pore sizes together with the much improved electron–hole separation and light utilisation of the Cu2O‐decorated MTBs. The H2 evolution rates achieved with the Cu2O‐decorated MTBs are one order of magnitude higher than those achieved by commercial P25 TiO2.
Ionic Grubbs–Hoveyda Complexes for Biphasic Ring‐Opening Metathesis Polymerization in Ionic Liquids: Access to Low Metal Content Polymers
Authors: Ferraz Camila P. , Autenrieth Benjamin , Frey Wolfgang , Buchmeiser Michael R.
Published: October 2013

A novel ionic metathesis catalyst, [Ru(1‐CH3‐4‐CO2Py+)2(IMesH2)(CH‐2‐{2‐PrO}‐5‐NO2C6H3)][OTf−]2 (3 b; IMesH2=1,3‐dimesitylimidazolin‐2‐ylidene, Py=pyridine), has been prepared. 3 b and the Grubbs–Hoveyda catalysts [Ru(1‐CH3‐4‐CO2Py+)2(IMesH2)(CH‐2‐{2‐PrO}C6H4)][OTf−]2 (3 a) and [RuCl(1‐CH3‐4‐CO2Py+)(IMesH2)(CH‐2‐{2‐PrO}C6H4)][OTf−] (5 a) were used for ring‐opening metathesis polymerization (ROMP) reactions under both homogeneous and biphasic liquid–liquid conditions by using the ionic liquid 1‐butyl‐2,3‐dimethylimidazolium tetrafluoroborate ([BDMIM+][BF4−]) and toluene. All catalysts were active in the ROMP of norborn‐2‐ene‐based monomers, with cis‐cyclooctene and dicyclopentadiene providing good yields under homogeneous conditions and complex 5 a the most active catalyst. With all catalysts, the use of a chain transfer agent (CTA) allowed for the synthesis of polymers with low metal contents between 10 and 80 ppm, corresponding to a ruthenium removal of 98–99.8 % without any additional purification step. In addition, the use of a CTA allowed for recycling experiments under biphasic conditions, in which 3 a and 5 a were particularly active for several cycles.
Convection Heat Transfer of CO2 at Supercritical Pressures in Microtubes
Authors: Yang F.‐Y. , Wang K. , Liu T. , Wang Y.‐Q. , Liu Z.‐C.
Published: October 2013

Convection heat transfer of supercritical pressure CO2 in microtubes as well as characteristics of fluid flow and heat transfer were investigated. Alterations of physical properties of supercritical CO2 and the impact of buoyancy on the heat transfer were analyzed when the inlet Reynolds (Re) number of CO2, diameter of heat exchanger, and inlet Re of cooling water were changed. The temperatures of hot fluid in numerical simulations from several classical turbulence calculation models were compared with experimental results from the literature. The physical properties of CO2 changed significantly around the critical point, causing a distinct decline of buoyancy and strengthening of heat transfer.
Determination of Amino Acid Enantiopurity and Absolute Configuration: Synergism between Configurationally Labile Metal‐Based Receptors and Dynamic Covalent Interactions
Authors: Scaramuzzo Francesca A. , Licini Giulia , Zonta Cristiano
Published: October 2013

Reliable determination of the enantiomeric excess of free amino acids can be obtained by measuring the induced circular dichroism of a multicomponent assembly formed by a modified tris(2‐pyridylmethyl)amine ligand, a zinc salt, and the amino acid of interest. The systems furnish reliable information for all natural amino acids.
Numerical Simulation of Concentration‐Induced Marangoni Convection at Single Rising Droplets
Authors: Engberg Roland F. , Wegener Mirco , Kenig Eugeny Y.
Published: October 2013

Beim Stofftransport an einem aufsteigenden Tropfen können Konzentrationsgradienten zu einer Variation der Grenzflächenspannung entlang der Phasengrenze führen und Marangoni‐Konvektion hervorrufen. Dadurch wird nicht nur der Stofftransport intensiviert, sondern auch das Aufstiegsverhalten des Tropfens beeinflusst. Um diese Phänomene mittels Strömungssimulationen zu untersuchen, wurde ein CFD‐Code entwickelt und in das CFD‐Paket OpenFOAM® implementiert, der der Kopplung von Impuls‐ und Stofftransport sowie der Verformung des Tropfens Rechnung trägt. Hier werden die Ergebnisse von 3D‐Simulationen vorgestellt und validiert.
Who benefits from market expansion?
Authors: Li Tieshan
Published: October 2013

This article presents a study of the effects of both symmetric and asymmetric market expansion on two retailers and their consumers. Envisioning two retailers along a Hotelling line, this article describes both the symmetric and asymmetric expansion of the market; the most interesting results occur when expansion is asymmetric. Applying game theory and showing the results numerically, I find three categories of unit‐distance moving costs incurred in three scenarios: when both retailers choose to move, when only one retailer chooses to move, and when neither retailer chooses to move. With fixed moving costs, moving is the dominant strategy for the retailer close to market expansion. Surprisingly, the retailer located the farthest away from the expansion has the highest profits. Copyright © 2013 ASAC. Published by John Wiley & Sons, Ltd.
Effects of morphine and aminophylline on the severity of obstruction to left ventricular outflow in idiopathic hypertrophic subaortic stenosis: Potential adverse effects in treatment of pulmonary edema
Authors: Awan N. A. , Miller R. R. , Demaria A. N. , Lee G. , Mason D. T.
Published: October 2013

Although morphine sulfate and aminophylline are commonly employed in the management of acute pulmonary edema of diverse etiologies including idiopathic hypertrophic subaortic stenosis (IHSS), the effects of morphine and aminophylline on left ventricular (LV) outflow obstruction in IHSS are unknown. Thus to determine the actions of morphine and aminophylline in IHSS, seven patients with IHSS (mean peak resting systolic gradient 16 mmHg, mean Valsalva provoked gradient 87 mmHg) received 5 mg morphine intravenously and simultaneous LV and brachial arterial pressures were continously monitored and cardiac outputs obtained. On return to control hemodynamics, 250 mg aminophylline was infused in three patients and hemodynamics repeated. Peak increase in gradient with morphine occurred in 5 min in each patient and average maximal gradient was 48 mmHg (p<0.001). Peak LV systolic pressure increased 158 to 182 mmHg (p<0.05); LV end‐diastolic pressure declined 12 to 8 mmHg (p<0.005); cardiac index decreased 3.18 to 2.89 l/min/m2 (p<0.005); while heart rate and total systemic vascular resistance were unchanged (p>0.05). Aminophylline increased peak gradient to 57 mmHg; lowered LV end‐diastolic pressure by 2 mmHg; decreased total systemic vascular resistance 1610 to 1120 dyne s · cm−5; while cardiac index was unchanged. Therefore morphine and aminophylline can rapidly increase LV outflow obstruction to marked extents in IHSS. These data indicate morphine worsens subaortic stenosis by decrease in LV preload through systemic venodilation, whereas aminophylline increases intraventricular gradient predominantly by peripheral arterial dilation. Thus morphine and aminophylline should be avoided, or used cautiously in low doses, in management of acute pulmonary edema in IHSS.
The ischemic segment and left ventricular function during exercise angina
Authors: Rentrop P. , Karsch K. R. , Nitsche K.
Published: October 2013

Improvement of the quality of transpulmonary left ventriculograms by exercise was demonstrated in 5 patients in a pre‐study. In the main study transpulmonary left ventriculography was performed in 10 patients with coronary artery disease (CAD) at rest and during exercise, producing maximum angina pectoris (AP). Left ventricular pressure was recorded simultaneously. The extent of CAD, demonstrated in all patients by coronary angiography, was quantitated by a score. In the exercise ventriculograms, local wall motion was quantitated by 14 hemiaxes. During exercise AP, all patients developed wall motion abnormalities not present at rest. There was a significant linear correlation between coronary score and number of abmormally shortening hemiaxes (< 30% shortening) during exercise‐AP (y = 0.16 × + 4.34; r = 0.933). The number of anormal hemiaxes correlated significantly (p < 0.05) with left ventricular enddiastolic pressure (LVEDP), dp/dt min, endsystolic volume index, enddiastolic volume index, ejection fraction, stroke work index, minute work, compliance SV/ Δ PD/ESV, and cardiac index. During exercise AP the extent of ischemic wall motion abnormalities is determined by localization and severity of coronary artery lesions. The extent of ischemic impairment of wall motion determines the severity of impairment of left ventricular pump function, filling pressure, and maximum speed of relaxation. Transpulmonary left ventriculography during exercise AP is a safe and relatively simple method to quantitate the extent of ischemic wall motion abnormalities. It could be useful in the selection of patients for coronary artery surgery and in the assessment of the results of this operation.
Left ventricular end‐diastolic pressure response to atrial pacing in idiopathic mitral valve prolapse
Authors: Feitosa G. S. , Bentivoglio L. G. , Uricchio J. F. , Meister S. G. , Frankl W. S.
Published: October 2013

The response of several parameters of left ventricular function to right atrial pacing was compared in 21 patients with idiopathic mitral valve prolapse and 10 normal patients. An inability to appropriately lower left ventricular end‐diastolic pressure with increasing rates was demonstrated in the mitral valve prolapse group. This abnormality was not related to mitral regurgitation or factors other than ventricular performance per se.
Pre‐infarction angina secondary to calcific aortic stenosis with bernheim's effect
Authors: Huang M. T. C. , Goodman M. A. , Delaney T. B.
Published: October 2013

Pre‐infarction angina, in the absence of coronary artery disease, was found in a 62 year‐old man with severe calcific aortic stenosis. After application of intra‐aortic balloon pump counter‐pulsation, the condition was stabilized, and coronary arteriograms were safely carried out. Interestingly, an elevated right atrial and right ventricular end‐diastolic pressure with an associated Bernheim's effect was demonstrated by cardiac catheterization. The hemodynamics of the right heart returned to normal after surgical correction of the aortic stenosis. The clinical indications for intra‐aortic balloon pump counterpulsation in this setting are discussed.
Technetium‐99m stannous pyrophosphate myocardial scintigraphy: Serial imaging to detect myocardial infarcts in patients
Authors: Falkoff M. , Parkey R. W. , Bonte F.J. , Lewis S. , Buja L.M. , Dehmer G. , Willerson J. T.
Published: October 2013

Typically, technetium‐99m stannous pyrophosphate (99mTc‐PYP) myocardial scintigrams become abnormal within 10‐12 h following acute myocardial infarction. Ordinarily, the 99mTc‐PYP scintigrams become increasingly abnormal between 24 and 72 h following the infarct and then become normal 6‐7 days after the event. However, occasional patients and their 99mTc‐PYP myocardial scintigrams deviate from this expected pattern by initially developing an abnormal 99mTc‐PYP scintigram as late as 4‐5 days following an acute myocardial infarction. Others retain “persistently abnormal” 99mTc‐PYP myocardial scintigrams after their myocardial infarcts. The clinical importance and potential prognostic importance of these deviations from the expected patterns with 99mTc‐PYP myocardial imaging are discussed and the need for serial myocardial imaging is emphasized.
Noninvasive assessment of segmental left ventricular wall motion: Its clinical relevance in detection of ischemia
Authors: Pichler M.
Published: October 2013

Newly developed noninvasive techniques, using fluoroscopic, electromagnetic, ultrasonic and nuclear medical devices, now make evaluation of segmental wall motion (SWM) widely applicable to man. Experiments in open chest animal preparations have demonstrated that SWM abnormalities (SWMA) are sensitive and specific markers of ischemia. Following coronary occlusion in closed chest dogs, using various techniques, we observed the same sequence of SWMA over a similar time course.

In 122 angiographically documented patients, SWMA assessed by stress cardiokymography (CKG) revealed a sensitivity of 74% and a specificity of 94% in detecting coronary heart disease (CHD). The combined predictive power of stress ECG/CKG was superior to either test alone. Using radionuclide equilibrium scintigraphy and sitting bicycle exercise, stress induced SWMA revealed a sensitivity of 84% in detecting CHD.

SWMA were detected in nearly all patients 24 h after acute transmural myocardial infarction (MI). These abnormalities extended beyond the location predicted by ST segment elevation and Q waves in the ECG, significantly more in anterior (15/16) than inferior (9/16) MI (p < 0.05). In inferior MI, precordial ST segment depression was frequently (8/10) associated with anterior SWMA, indicative of ischemia rather than of a reciprocal electrical phenomenon. Scintigraphic assessment of left ventricular SWM correlated poorly with calculated CK‐MB infarct size (r = 0.64), suggesting that left ventricular function is determined not only by the necrotic zone but is also related to dysfunction of ischemic segments. SWM of the infarcted as well as the remote zone of the left ventricle showed no consistent directional changes within 10 days after infarction.

In conclusion, noninvasive analysis of SWM is of clinical relevance 1. during diagnostic stress testing to detect ischemia, 2. in chronic stable CHD to assess the extent of mechanical dysfunction, 3. in acute MI to localize and assess extent and severity of regional myocardial dysfunction.
Systolic honk in heart failure: Its origin and mechanism of production
Authors: Sheikh M. U. , Ali N.
Published: October 2013

Systolic honks have so far been synonymous with prolapse of the mitral valve leaflet. Evidence of tricuspid valve involvement in two cases is presented. These patients developed systolic honk during the deterioration of their congestive heart failure. Simultaneous recordings of echocardiograms and phonocardiograms showed fluttering of the tricuspid valve, coinciding with the systolic honk. This fluttering was not seen when honk was absent. The mechanism of production of this honk is discussed.
Persistence of improved exercise tolerance and degree of revascularization after coronary bypass surgery. A prospective randomized study
Authors: Frick M. H. , Harjola P.‐T. , Valle M.
Published: October 2013

Exercise tolerance was repeatedly determined over a 2‐year period in a series of 100 patients with coronary heart disease randomly allocated for medical therapy and coronary bypass surgery. The surgical group had a consistently better exercise tolerance than the medical group during the whole follow‐up. Completeness of the revascularization, assessed by repeated graft and native vessel angiography, resulted in a marked improvement whereas incompletely revascularized patients exhibited only a marginal improvement which, nevertheless, to some degree exceeded the result of medical management alone.

It is concluded that coronary bypass surgery and medical therapy, when indicated, result in markedly better exercise tolerance than medical management alone. This improvement persists up two years after the operation and is largely dependent on the completeness of the revascularization.
Beneficial effect of continuation of propranolol through coronary bypass surgery
Authors: Boudoulas H. , Lewis R. P. , Snyder G. L. , Karayannacos P. , Vasko J. S.
Published: October 2013

The safety and beneficial effect of continuation of propranolol (Pr) through coronary bypass surgery (CBS) was studied in two groups of patients. In the control group (50 patients) Pr was discontinued 24 h before CBS without reinstitution afterwards. In the propranolol group the drug was maintained up to 4 to 10 h before surgery and was restarted within 24 h afterwards. The incidence of subendocardial myocardial infarction was significantly lower in the Pr group (1 out of 30 vs 10 out of 50, p < 0.05) while the incidence of transmural infarction was the same in both groups (3 out of 30, 10 %, vs 5 out of 50, 10%). The incidence of supraventricular tachycardias during the first three postoperative days was significantly lower in the propranolol group compared to control (5% vs 30%, p < 0.01). The 24 h urinary epinephrine and norepinephrine excretion was significantly greater than normal the day before surgery (136 ± 12 vs 39 ± 4 μg/24 h, p < 0.01), and was still high two weeks after surgery (115.1 ± 14 μg/24 h). There were no complications related to propranolol. The left ventricular function as measured from the systolic time intervals was the same pre‐and postoperatively in both groups. The results of this study show that administration of propranolol up to 4 h before coronary bypass and reinstitution immediately afterwards is safe and beneficial.
Exercise 201thallium myocardial scans in patients with disease limited to the secondary branches of the left coronary system
Authors: Iskandrian A. S. , Scherer H. , Croll M. N. , Bemis C. E. , Segal B. L. , Kimbiris D. , Wallner R.
Published: October 2013

Coronary disease (≥ 50% narrowing) confined to only the diagonal branch of the left anterior descending artery or to the marginal branch of the left circumflex artery, or both, is uncommon. Only 19 patients with disease as defined above were identified in a group of 1000 consecutive patients with an angiographic diagnosis of coronary heart disease. All 19 patients were studied because of angina pectoris and all underwent stress myocardial perfusion scintigraphy with 201Tl (20lthallium) during maximal treadmill exercise testing (exercise electrocardiogram: E/ECG). Ten patients (52%) had positive E/ECG's; seven patients (36%) had positive 201Tl and 13 patients (68%) had one or both tests positive. In 12 patients, the diseased branch was small, i.e. it supplied a comparatively small portion of myocardium, and in seven patients it was determined to be large. The 201Tl test results were positive in four out of seven patients (57%) with large diseased branches, as compared with three out of 12 (25%) with small diseased branches (p: NS). Also, three out of seven patients (42%) with large diseased branches had positive E/ECG's as compared with seven out of 12 patients (58%) with small diseased branches (p: NS). Patients with branch disease may present with typical angina pectoris, however, they are rare and thus not likely to account for the majority of false‐negative 201Tl test results among symptomatic patients with CHD. Approximately one‐third of the patients with branch disease have positive 201Tl test results, one‐half have positive E/ECG's, and in two‐thirds, one or both tests are positive.
Beneficial effects of prolonged low dose dopamine in hospitalized patients with severe refractory heart failure
Authors: White D. H. , Crawford M. H. , O'Rourke R. A.
Published: October 2013

In 10 hospitalized patients with severe congestive heart failure refractory to standard medical therapy for three days, low dose intravenous dopamine (2‐4 μg/kg/min) was infused for 48 h. Heart rate and systolic blood pressure were unchanged throughout the study. Mean pulmonary artery wedge pressure decreased significantly during the dopamine infusion from 27 ± 6 (SD) to 18 ± 6 mmHg (p < 0.01) and cardiac output increased from 3.2 ± 1.1 to 4.6 ± 0.8 l/min (p < 0.001). A diuresis was initiated in all patients and there was a significant weight loss during the study which averaged 5 lbs (p <0.01). All patients improved symptomatically from class IV (NYHA) to class III and were more responsive to conventional therapy after the study. No adverse reactions were noted in this dose range. We conclude that low dose intravenous dopamine is efficacious in improving hemodynamics and initiating a diuresis in patients with severe refractory congestive heart failure.
Studies on digitalis. 23. Blood‐brain barrier of digitoxin in humans
Authors: Storstein L. , Nore A. K. , Sjaastad O.
Published: October 2013

Data on the cerebrospinal fluid concentrations of digitoxin in man have been lacking. Aim of the present study was to investigate serum and cerebrospinal fluid concentrations of digitoxin. Eleven patients with normal cerebrospinal fluid composition, normal serum albumin values, normal renal and hepatic function and normal hematologic tests were given a single dose of 0.6 mg digitoxin. Serum and cerebrospinal fluid were collected 16 h after the dose, and assayed by radio‐immunoassay, serum digitoxin protein binding was measured with equilibrium dialysis.

Mean serum digitoxin concentration was 12.4 ng/ml (SD 2.6) and mean CSF concentration 0.84 ng/ml (SD 0.22) giving a CSF/serum ratio of 0.07 (SD 0.03). Serum digitoxin protein binding was 97.4% (SD 0.4) and the calculated CSF/free serum digitoxin ratio was thus 2.94 (SD 1.43).

Free serum digitoxin concentrations are more relevant for pharmacologic effect than total serum digitoxin concentrations and also for passage into the central nervous system. Using free drug concentrations the ratio between digitoxin in serum and CSF is lower than reported values for digoxin indicating a higher penetrance of digitoxin into the central nervous system. This corresponds well with the higher lipid solubility of digitoxin. Post mortem studies have shown that concentrations are higher in cerebral tissue than in CSF for digoxin. Determination of CSF concentrations thus probably underestimates the penetrance of digitalis glycosides into the central nervous system, but may serve as a useful indicator of variance among digitalis glycosides.
Cardiac emission tomography in patients using 201Thallium. A new technique for perfusion scintigraphy
Authors: Dymond D. S. , Stone D. L. , Elliott A. T. , Britton K. E. , Spurrell R. A. J.
Published: October 2013

The distribution of 201thallium (Tl) in the myocardium has been studied by the new technique of emission tomography, and compared with standard gamma camera images in 5 patients. Tomographic imaging was carried out using a dual‐detector scanner operating under the single‐photon technique. Initial results have been promising, with visualisation of resting perfusion defects in patients with recent infarction and those with ventricular aneurysms. Emission tomography has also been performed at exercise, and has shown tracer deficits in the distribution of significant coronary stenoses. This new approach to myocardial perfusion scintigraphy may lead to improved sensitivity for detecting apical and inferior wall abnormalities by providing depth information not available from a conventional two‐dimensional image.
The echocardiographic association of mitral valve prolapse and mitral anulus calcification
Authors: McLean J. , Felner J. M. , Whipple MD R. , Morris D. , Schlant R. C.
Published: October 2013

Mitral anulus calcification (MAC) and mitral valve prolapse (MVP) are frequently diagnosed conditions. We studied two patients with mild or moderate mitral regurgitation who demonstrated both MAC and MVP on angiography and echocardiography. M‐mode echocardiography is probably the definitive test for confirming the presence of MVP. Echocardiography is moderately sensitive in the diagnosis of cardiac calcification, such as MAC, but M‐mode echocardiography may not detect the MAC in the majority of patients with both MVP and MAC demonstrated by angiography.
Coronary artery spasm: Its role in the pathogenesis of myocardial ischemia
Authors: Chahine R. A.
Published: October 2013

The role of coronary artery spasm in the production of myocardial ischemia has recently become the focus of increased attention. This phenomenon is now well established as a causative mechanism underlying the resting chest pain attacks in Prinzmetal's variant angina. There is also evidence that coronary spasm may play a more significant role in the broad spectrum of ischemic heart disease than can be documented by current techniques. The autonomous nervous system constitutes a major element in the pathophysiology of spasm. Coronary arteriography, in spite of important limitations, remains the only technique for final documentation of this phenomenon, but radionuclide scintigraphy appears to be promising. Nitroglycerin is effective for the relief of the acute attack, while long acting nitrates and the calcium antagonists: nifedipine, perhexiline and verapamil are useful in the prevention of recurrences.
Aorta—Saphenous vein anastomoses markers
Authors: Halseth W. L. , Elliott D. P. , Walker E. L. , Meza F.
Published: October 2013

I have read with interest the article by Drs. Halseth, Elliott, Walker, and Meza, “Angiographic Restudy of Coronary Artery Bypass Grafts Simplified by a Marker.”

We have had the opportunity to study 1,093 postoperative vein bypass patients using both the Sones and the Judkins techniques since January, 1970. Since that time, our surgeons have used both a stainless steel ring and metallic clips to mark the site of anastomoses of the proximal portion of the saphenous vein bypass graft to the aorta. We have had no difficulty in locating the bypass with either marker in place and support the findings of Drs. Halseth et al. in this regard.
The altered baroreceptor response to nitroglycerin in congestive heart failure
Authors: Faxon D. P. , Gross S. , Tilney C. , Ryan T. J.
Published: October 2013

The use of nitroglycerin as a vasodilator in the treatment of congestive heart failure has demonstrated that the hemodynamic response is related to the degree of left ventricular dysfunction. Little emphasis has been placed on the mechanisms responsible for the variability in heart rate response to nitroglycerin. To study this problem, 33 patients with a variety of chronic cardiac disorders were given 0.4 mg of nitroglycerin sublingually. An increase in heart rate of <3 beats/min to sublingual nitroglycerin allowed a clear identification of a group of patients who had a left ventricular end‐diastolic pressure >18 mmHg or pulmonary artery mean pressure >22 mmHg, and who had improvement in hemodynamic parameters following nitroglycerin. This alteration in baroreceptor sensitivity appears to be related to the level of left ventricular filling pressure, and can be used as a simple bedside means of identifying a group of patients who benefit the most from the vasodilator action of nitroglycerin.
Long‐term comparison of metoprolol and methyldopa in the treatment of hypertension
Authors: Lorimer A. R. , Barbour M. , Hillis W. S. , Lawrie T. D. V. , Stoker J. B. , Sreeharan N. , Leanage R. U. , Linden R. J.
Published: October 2013

The effect of the cardioselective beta‐adrenoreceptor blocking compound, metoprolol, was compared with methyldopa in the long‐term management of hypertension. Thirty patients given metoprolol and twenty‐six given methyldopa were treated for 2 years. The maximum dose of metoprolol was 200 mg twice daily (average 308 mg) and of methyldopa 1,000 mg twice daily (average 1,120 mg). Blood pressure was similar at entry to the study (metoprolol 177/110 mmHg and methyldopa 181/111 mmHg). After 2 years of treatment the blood pressure levels were again similar (metoprolol 149/91 mmHg and methyldopa 148/91 mmHg). Erect pressures were lower in the methyldopa group, but there was no difference between supine and erect blood pressure levels in those on metoprolol. At an exercise load of 300 and 600 kpm the increase in systolic pressure was significantly less in the metoprolol group. The proportional increase in systolic and diastolic pressure in response to a standardized stress situation was reduced by treatment with metoprolol but not by methyldopa. Tolerance to therapy did not develop in either group.

The main difference between metoprolol and methyldopa was in the incidence and severity of side effects. Four patients were withdrawn from the metoprolol group. Seventeen were withdrawn from methyldopa mainly because of side effects including drowsiness, depression, skin rash, and impotence. Six patients on metoprolol and seventeen on methyldopa continued on therapy although side effects were present.

It is concluded that metoprolol and methyldopa lower blood pressure to the same extent, but metoprolol is advantageous because of a lower incidence of side effects.
Clinical and hemodynamic results of extracardiac conduit reconstruction of the pulmonary artery
Authors: Clarkson S. , Sade R. M. , Hohn A.
Published: October 2013

To evaluate the efficacy of pulmonary artery construction with a prosthetic conduit we have reviewed 25 operations in 22 of our patients. Early mortality was 12.0%, late mortality 5.3%. Up to 13 years postoperatively, 93.8% of the survivors are asymptomatic. Of 12 patients surviving more than 1 year, 11 have been catheterized after 1‐11 years. Five had prior aortopulmonary shunts (mean duration 7.3 years); highest postrepair pulmonary artery pressure was 40 mmHg. Of seven recatheterized xenograft conduits, none had severe and four had mild obstruction. Reconstruction of pulmonary artery with xenograft conduit produced good clinical results. Long duration of aortopulmonary shunt prior to repair did not result in severe pulmonary artery hypertension. Obstruction of xenograft conduit has not been a major problem in our patients, but when necessary, reoperation for obstruction can be carried out safely as late as 11 years after the operation.
Coronary arterial spasm in angina at rest associated with transient ST‐segment changes
Authors: de Servi S. , Specchia G. , Angoli L. , Bramucci E. , Mussini A. , Marinoni G. P. , Salerno J. , Bobba P.
Published: October 2013

In order to clarify the role of coronary arterial spasm in the pathogenesis of angina at rest, coronary arteriography was performed during spontaneous chest pain or following intravenous administration of ergonovine maleate in 40 patients with angina at rest. Coronary vasospasm was demonstrated in 23 patients with ST‐segment elevation during chest pain (group I), in 7 with ST‐segment depression (group II), and in 4 with both ST‐segment depression and elevation (group III).

Complete spastic occlusion of the proximal or of the midportion of the left anterior descending artery was always associated with ST‐segment elevation in anterior leads. In contrast, transient ST‐segment depression in anterior leads was associated with diffuse narrowing of the left anterior descending artery with slow progression of the contrast medium, or complete occlusion of a small branch or of the distal segment of the left anterior descending artery. ST‐Segment elevation in inferior leads was associated with complete spastic occlusion or with significant spastic narrowing of the right coronary artery or of the circumflex artery.

We conclude that coronary spasm can be demonstrated in a selected cohort of patients with angina at rest associated with transient ST‐segment changes. In some cases the site and the severity of the spasm may produce varying degrees of ischemia, thus determining the direction of the ST‐segment shift.
Changes in coronary anatomy and left ventricular function from the acute to the chronic stage of myocardial infarction
Authors: Blanke H. , Karsch K. R. , Kreuzer H. , Rentrop P.
Published: October 2013

Coronary angiography was performed in the acute stage of myocardial infarction in 65 patients. The infarct‐related vessel was occluded in 50 patients; it was narrowed >90% in the remaining 15 patients.

Control angiography was performed 55±46 d after acute myocardial infarction in 18 patients. In the chronic stage, five of thirteen previously occluded vessels showed antegrade filling of the distal segment. The narrowing at the site of previous obstruction was 80‐95%. In two of five patients with a subtotal stenosis, the lumen of the infarct‐related vessel was clearly larger in the chronic stage. The end‐diastolic volume index increased significantly from 86±23 ml/m2 in the acute stage to 110±35 ml/m2 in the chronic stage (p<0.001). The increase in the end‐systolic volume index from 42±15 ml/m2 to 63±31 ml/m2 was also statistically significant (p<0.005). Stroke volume index, ejection fraction, and the length of the akinetic segment (AKS) did not change significantly. There was a weak correlation between the end‐systolic volume index and the length of the AKS in the acute stage (r = 0.489, p<0.05) and a better correlation in the chronic stage (r = 0.602, p<0.01). The ejection fraction and the length of the AKS correlated in the chronic stage only (r = 0.795, p<0.001).

In contrast to the total group, three patients showed improvement in left ventricular pump function. In all three patients there was a collateral flow to the infarct area during the acute stage of myocardial infarction. In two of these patients there was spontaneous recanalization of the infarct vessel. However, vascularity of the infarct area during the acute stage was also found in eleven patients without improvement of left ventricular pump function. Two of these showed recanalization of the infarct vessel. In all four patients with a proximal occlusion of a major coronary artery and avascularity of the infarct area, there was impairment of left ventricular function and an increase in the length of the AKS.
Triple origin of left coronary arteries from right coronary artery: Unusual case of single coronary artery
Authors: Vuthoori S. , Waisser E. , Angelini P.
Published: October 2013

A rare case of coronary anomaly is presented: all of the coronary arteries originated from a single ostium located in the right coronary cusp. No clinical evidence of coronary pathology was recognized until the age of 57 years when the patient was found to have coronary obstructive disease. The single coronary artery had a main branch corresponding to the usual dominant right coronary artery. Three other branches separated from this and vascularized the areas normally receiving the circumflex and ramus medianus, the left anterior descending, and a large septal branch.
Right ventricular obstruction secondary to intracardiac metastatic osteosarcoma
Authors: Wise N. K. , Peter R. H. , Wechsler A. S. , Moore J. O. , Saltzman H. A.
Published: October 2013

A 30‐year‐old female with a history of surgically treated osteosarcoma 2 years prior to admission presented with progressive dyspnea and cyanosis. Physical examination was otherwise negative. Cardiac catheterization demonstrated a right ventricular mass lesion. At surgery, a metastatic osteosarcoma filling the entire right ventricle and extending from the pulmonary valve across the tricuspid valve and into the right atrial cavity was partially excised. Despite marked improvement postoperatively, she died 33 d after surgery. Postmortem findings were unusual in that the heart represented the sole site of metastasis. The diagnostic approach to cardiac symptoms from malignancy is discussed in relation to this patient.
Myoglobin or enzymes for a rapid evaluation of infarction diagnosis?
Authors: Mezger V.A. , Kahles H. , Stellwaag M. , Spieckermann P. G.
Published: October 2013

Recently published clinical studies on patients with acute myocardial infarction (AMI) have documented that radioimmunologically determined serum peak concentrations of myoglobin (Mb) precede enzyme peak values. It has, therefore, been concluded that Mb (molecular weight 17,600) is liberated earlier from damaged myocardium than, for example, creatine kinase (CK, molecular weight 80,000). As rapid diagnosis is essential in the management of patients suffering from AMI, we have studied the liberation of cardiac enzymes and Mb using a nonrecirculating perfusion system. The release of malate dehydrogenase (MDH), lactate dehydrogenase (LDH), CK, and Mb from isolated guinea pig heart preparations was induced by anaerobic coronary perfusion at a constant flow rate. Thirty minutes after onset of anoxia there was a simultaneous increase in MDH, LDH, and Mb release. Maximum levels were reached between 120 and 180 min. The release curves for enzymes and Mb were approximately parallel. Close correlations exist between LDH/MDH (r = 0.94), CK/MDH (r = 0.98), LDH/Mb (r = 0.89), and MDH/Mb (r = 0.91). Based on these results and on calculations related to invasion and elimination kinetics, we suggest that the early peak of serum Mb in patients with AMI does not reflect a prior Mb release but depends on the more rapid rate of elimination of Mb from serum in comparison to enzymes.
Significance of echocardiographic left atrial enlargement in aortic stenosis
Authors: Chandraratna P. A. N. , Aronow M. S. , Aronow W. S.
Published: October 2013

This study investigated the significance of echocardiographic left atrial enlargement as measured by the left atrial dimension corrected for body surface area in 24 patients with pure aortic stenosis established by cardiac catheterization. Echocardiographic evidence of left atrial enlargement occurred in 11 of 15 patients (73%) with an aortic valve area below 0.8 cm2 and in none of nine patients (0%) with an aortic valve area above 0.8 cm2, p < 0.0025. All 11 patients (100%) with an enlarged left atrial dimension had an increased diastolic left ventricular dimension, whereas 1 of 13 patients (8%) with a normal left atrial dimension had an increased diastolic left ventricular dimension, p < 0.00001. The 11 patients (100%) with an enlarged left atrial dimension had increased posterior left ventricular wall thickness, whereas 2 of 13 patients (13%) with a normal left atrial dimension had increased posterior left ventricular wall thickness (p < 0.0005). These data lead one to conclude that in patients with pure aortic stenosis, echocardiographic evidence of left atrial enlargement as measured by an increased left atrial dimension corrected for body surface area should lead one to suspect severe aortic stenosis.