tbuckley/cabot-search huggingface dataset:
Tailored thrombolytic therapy. A perspective.
Authors: M LSimoons, A EArnold
Journal: Circulation (1993)

BACKGROUNDIn contrast with current standard regimens, it seems more appropriate to tailor thrombolytic therapy to individual patient characteristics. A proposed model for such tailored therapy is based on individual assessment of benefits and risks of thrombolytic therapy, taking into account the response of individual patients to the therapy given.METHODS AND RESULTSPotential benefits of thrombolysis in individual patients can be predicted by use of demographic patient characteristics (age, sex, history of previous infarction) together with indicators of the ischemic area at risk (total ST segment deviation) and treatment delay. Using these parameters, the number of lives saved by thrombolytic therapy for specific patient characteristics can be estimated. Similarly, the risk of intracranial hemorrhage during thrombolytic therapy can be estimated from the patient's age, blood pressure at admission, and body weight. Depending on benefit/risk estimates, a choice can be made between regimens with high, med...
Effect of lovastatin on early carotid atherosclerosis and cardiovascular events. Asymptomatic Carotid Artery Progression Study (ACAPS) Research Group.
Authors: C DFurberg, H PAdams, W BApplegate, R PByington, M AEspeland, THartwell, D BHunninghake, D SLefkowitz, JProbstfield, W ARiley
Journal: Circulation (1994)

BACKGROUNDHMG CoA reductase inhibitors (or statins), a new class of lipid-lowering compounds, have raised expectations for more widespread use than that of the older lipid-lowering drugs. Not only are they more effective in lowering LDL cholesterol, but they are better tolerated as well. No data exist concerning the effect of statins on early carotid atherosclerosis and clinical events in men and women who have moderately elevated LDL cholesterol levels but are free of symptomatic cardiovascular disease.METHODS AND RESULTSLovastatin (20 to 40 mg/d) or its placebo was evaluated in a double-blind, randomized clinical trial with factorial design along with warfarin (1 mg/d) or its placebo. This report is limited to the lovastatin component of the trial. Daily aspirin (81 mg/d) was recommended for everyone. Enrollment included 919 asymptomatic men and women, 40 to 79 years old, with early carotid atherosclerosis as defined by B-mode ultrasonography and LDL cholesterol between the 60th and 90th percentiles. Th...
Two-dimensional echocardiographic demonstration of left atrial thrombi in patients with prosthetic mitral valves.
Authors: F LMikell, R WAsinger, TRourke, MHodges, BSharma, G SFrancis
Journal: Circulation (1979)

Although M-mode echocardiography (MME) is not a reliable method for detecting left atrial thrombi, recent reports suggest that two-dimensional echo (2DE) may be more effective than MME in identifying intracardiac thrombi. In three patients with prosthetic mitral valves who presented with either arterial embolization or prosthetic valvular dysfunction, 2DE demonstrated left atrial masses consistent with thrombi, while MME was either negative (two patients) or suspicious (one patient) for left atrial thrombus. Thrombi were documented by surgical or postmortem examination in all cases. Clear delineation of the atrial cavity and the margins of the masses, visualization on multiple echocardiographic views and comparison of serial examinations were helpful in identifying these masses as thrombi. In addition, the masses visualized had certain patterns of motion which seem unique and may allow characterization of atrial masses as thrombi.
Echocardiographic measurement of cardiac output using the mitral valve and aortic root echo.
Authors: A VLalani, S JLee
Journal: Circulation (1976)

The current echo method for measuring cardiac output (CO) has various technical limitations and is based on the assumptions that the left ventricle is not dilated and that it contracts uniformly. We have taken a different approach to measuring CO by echo: CO = cross-sectional area of aortic root X left ventricular ejection time X mean aortic flow velocity X heart rate. Using the Fick method, 34 measurements of CO were made in patients with normal aortic and mitral valves, with simultaneous echo recordings from the aortic and mitral valves. The systolic closure slope of the anterior mitral valve leaflet was assumed to represent the mean aortic flow velocity. CO by Fick and the proposed echo method correlated well, both in patients with (r = 0.94) and those without (r = 0.87) asynergy and the overall correlation was strong (r = 0.90). Using the conventional echo and Fick methods, a much weaker association was found between the two measurements in those patients with asynergy (r = 0.44) as opposed to those w...
A near infrared ratiometric platform based π-extended porphyrin metal-organic framework for O2 imaging and cancer therapy
Authors: Bo-Ru Xie, Yun Yu, Xin-Hua Liu, Jin-Yue Zeng, Mei-Zhen Zou, Chu-Xin Li, Xuan Zeng, Xian-Zheng Zhang
Journal: Biomaterials (2021)
Distribution and three-dimensional structure of intercellular junctions in canine myocardium.
Authors: R HHoyt, M LCohen, J ESaffitz
Journal: Circulation Research (1989)

Electrotonic coupling of cardiac myocytes at gap junctions may influence patterns of conduction in myocardium. To delineate the three-dimensional structure and distribution of intercellular junctions, we analyzed serial ultrathin sections of canine myocardium with transmission electron microscopy and disaggregated myocytes with scanning electron microscopy. Morphometric analysis of left ventricular myocardium sectioned in three orthogonal planes revealed that 80% of total gap junctional membrane occurred in large, ribbon-like gap junctions oriented transversely at cell end processes. The remaining 20% of gap junctional membrane was contained in small gap junctions located within plicate segments (interdigitating regions of cell-to-cell adhesion) of intercalated disks. In serial ultrathin sections, all gap junctions were contiguous with plicate segments. Thus, true lateral gap junctions do not exist in working ventricular myocytes and would not likely be able to withstand shear forces created by laterall...
Shall The Journal be Removed to Washington?
Authors: F. B. Davison
Journal: JAMA (1891)

<h3>To the Editor:</h3> —As many of the letters inThe Journalopposed to its removal to Washington are from the West, I write, as originally from New England and living East, to express my opinion and firm belief that the best interests ofThe Journalwill be served by keeping it in Chicago. The fact that full delegations of the profession in and near Washington will be at the meeting to vote for removal should induce delegates of the North, South and West to attend the meeting and vote against removal, so that the small percentage of membership favoring removal may not out-vote the vast majority opposed to removal from the remoteness of one party and nearness of the other party to the place of meeting. Fleetville, Lackawanna Co., Pa.
Cardiovascular effects associated with antidiuretic activity of vasopressin after blockade of its vasoconstrictor action in dehydrated dogs.
Authors: J FLiard
Journal: Circulation Research (1986)

In view of our previous findings that a specific antidiuretic (V2) agonist, 4-valine-8-D-arginine vasopressin, acutely increased cardiac output and heart rate in dogs, we examined the hypothesis that interaction with V2-like receptors might contribute to the hemodynamic response seen after blockade of the vasoconstrictor (V1) effect of arginine-vasopressin in dehydrated dogs. After 48 hours of water restriction which increased plasma vasopressin to 10.6 +/- 2.0 pg/ml, the V1 antagonist 1-(beta-mercapto-beta,beta-cyclopentamethylene propionic acid) 2-(O-methyl)tyrosine arginine-vasopressin, 10 micrograms/kg, was injected intravenously into six conscious dogs, and the combined V1 + V2 antagonist 1-(beta-mercapto-beta,beta,cyclopentamethylene propionic acid) 2-(O-ethyl)-D-tyrosine, 4-valine arginine-vasopressin, 10 micrograms/kg, was administered to another six dogs. Mean arterial pressure, cardiac output (electromagnetic flowmeter), and regional blood flows (radioactive microspheres) were measured before an...
Electrode radius predicts lesion radius during radiofrequency energy heating. Validation of a proposed thermodynamic model.
Authors: D EHaines, D DWatson, A FVerow
Journal: Circulation Research (1990)

Myocardial heating by transcatheter delivery of radiofrequency (RF) energy has been proposed as an effective means of arrhythmia ablation. A thermodynamic model describing the radial temperature gradient at steady state during RF-induced heating is proposed. If one assumes that RF power output is adjusted to maintain a constant electrode-tissue interface temperature at all times, then this thermodynamic model predicts that the radius of the RF-induced lesion will be directly proportional to the electrode radius. A total of 76 RF-induced lesions were created in a model of isolated canine right ventricular free wall perfused and superfused with oxygenated Krebs-Henseleit buffer. Electrode radius was varied between 0.75 and 2.25 mm. RF energy (500 kHz) was delivered for 90 seconds, and the power output was adjusted to maintain a constant electrode-tissue interface temperature of 60 degrees C. A strong linear correlation was observed between electrode radius and lesion radius in two dimensions: transverse (p ...
Effect of the angiotensin II blocker 1-Sar-8-Ala-angiotensin II on renal artery clip hypertension in the rat.
Authors: G JMacdonald, G WBoyd, W SPeart
Journal: Circulation Research (1975)

Twenty-four conscious male Wistar rats with hypertension induced by left renal artery clipping (two-kidney hypertension) were infused intravenously with 1-Sar-8-Ala-angiotensin II a competitive angiotensin II antagonist. The spectrum of responses was wide, ranging from a mild elevation in blood pressure to a marked fall in blood pressure, despite effective and specific angiotensin blockade in all cases. The change in blood pressure during 1-Sar-8-Ala-AII infusion activity showed a significant correlation with the level of plasma renin prevailing immediately before the infusion (r = - 0.78, P less than 0.01) but not with the prevailing blood urea level (r = 0.27, 0.1 greater than P greater than 0.05), the drgree of hypertension (r = 0.42, 0.1 greater than P greater than 0.05), or the time since clipping (r = 0.02, P greater than 0.05). There was no significant correlation between the degree of hypertension and the plasma renin activity (r = 0.42, 0.1 greater than P greater than 0.05). In rats with blood pr...
Endoscopic Ultrasound Share-Wave Elastography Of The Right And Left Hepatic Lobe Predicts Liver Cirrhosis: A Diagnostic Trial
Authors: C Robles-Medranda, R Oleas, R Del Valle, M Puga-Tejada, F Dal Bello, J Alcivar-Vasquez, H Alvarado, C Cifuentes, H Pitanga-Lukashok
Journal: Endoscopy (2021)

Aims We aim to evaluate endoscopic ultrasound share-wave elastography of the liver to predict liver cirrhosis.
Quantitative ultrasonic analysis of myocardium in patients with thalassemia major and iron overload.
Authors: FLattanzi, PBellotti, EPicano, FChiarella, AMazzarisi, CMelevendi, GForni, LLandini, ADistante, CVecchio
Journal: Circulation (1993)

BACKGROUNDPatients with beta-thalassemia major present with severe anemia and need continuous transfusion therapy. The consequent iron overload leads to hemochromatosis. Initial cardiac dysfunction has been documented even in thalassemics without clinical manifestations of heart failure as well as by conventional echocardiographic-Doppler techniques. The purpose of this study was to assess the acoustic quantitative properties of myocardium in patients with iron overload.METHODS AND RESULTSThirty-eight patients with beta-thalassemia major, without clinical signs of cardiac failure, and 20 age- and sex-matched young controls were studied by echocardiography. An on-line analysis of the ultrasonic radiofrequency signal was performed to obtain quantitative operator-independent measurements of the integrated backscatter (IB) signal of the ventricular septum and the posterior wall. The integrated values of the radiofrequency signal were normalized for the pericardial interface and expressed in percent (IB%). Tha...
Normal and Premature Adrenarche
Authors: Robert L Rosenfield
Journal: Endocrine Reviews (2021)

Adrenarche is the maturational increase in adrenal androgen production that normally begins in early childhood. It results from changes in the secretory response to adrenocorticotropin (ACTH) that are best indexed by dehydroepiandrosterone sulfate (DHEAS) rise. These changes are related to the development of the zona reticularis (ZR) and its unique gene/enzyme expression pattern of low 3ß-hydroxysteroid dehydrogenase type 2 with high cytochrome b5A, sulfotransferase 2A1, and 17ß-hydroxysteroid dehydrogenase type 5. Recently 11-ketotestosterone was identified as an important bioactive adrenarchal androgen. Birth weight, body growth, obesity, and prolactin are related to ZR development. Adrenarchal androgens normally contribute to the onset of sexual pubic hair (pubarche) and sebaceous and apocrine gland development. Premature adrenarche causes ≥90% of premature pubarche (PP). Its cause is unknown. Affected children have a significantly increased growth rate with proportionate bone age advancement that typically does not compromise growth potential. Serum DHEAS and testosterone levels increase to levels normal for early female puberty. It is associated with mildly increased risks for obesity, insulin resistance, and possibly mood disorder and polycystic ovary syndrome. Between 5% and 10% of PP is due to virilizing disorders, which are usually characterized by more rapid advancement of pubarche and compromise of adult height potential than premature adrenarche. Most cases are due to nonclassic congenital adrenal hyperplasia. Algorithms are presented for the differential diagnosis of PP. This review highlights recent advances in molecular genetic and developmental biologic understanding of ZR development and insights into adrenarche emanating from mass spectrometric steroid assays.
Smoking, Radiation Therapy, and Contralateral Breast Cancer Risk in Young Women
Authors: Anne S Reiner, Gordon P Watt, Esther M John, Charles F Lynch, Jennifer D Brooks, Lene Mellemkjær, John D Boice, Julia A Knight, Patrick Concannon, Susan A Smith, Xiaolin Liang, Meghan Woods, Roy Shore, Kathleen E Malone, Leslie Bernstein, Jonine L Bernstein
Journal: JNCI Journal of the National Cancer Institute (2021)

Abstract Evidence is mounting that cigarette smoking contributes to second primary contralateral breast cancer (CBC) risk. Whether radiation therapy (RT) interacts with smoking to modify this risk is unknown. In this multicenter, individually matched, case-control study, we examined the association between RT, smoking, and CBC risk. The study included 1521 CBC cases and 2212 controls with unilateral breast cancer, all diagnosed with first invasive breast cancer between 1985 and 2008 aged younger than 55 years. Absorbed radiation doses to contralateral breast regions were estimated with thermoluminescent dosimeters in tissue-equivalent anthropomorphic phantoms, and smoking history was collected by interview. Rate ratios (RRs) and 95% confidence intervals (CIs) for CBC risk were estimated by multivariable conditional logistic regression. There was no interaction between any measure of smoking with RT to increase CBC risk (eg, the interaction of continuous RT dose with smoking at first breast cancer diagnosis [ever/never]: RR = 1.00, 95% CI = 0.89 to 1.14; continuous RT dose with years smoked: RR = 1.00, 95% CI = 0.99 to 1.01; and continuous RT dose with lifetime pack-years: RR = 1.00, 95% CI = 0.99 to 1.01). There was no evidence that RT further increased CBC risk in young women with first primary breast cancer who were current smokers or had smoking history.
Body fat distribution and male/female differences in lipids and lipoproteins.
Authors: D SFreedman, S JJacobsen, J JBarboriak, K ASobocinski, A JAnderson, A HKissebah, E ASasse, H WGruchow
Journal: Circulation (1990)

The role of body fat distribution, as assessed by the ratio of waist-to-hip circumferences (WHR), in statistically explaining differences in levels of lipoproteins between men and women was studied using data collected in 1985-1986 from employed adults (mean age, 40 years). As compared with the 415 women, the 709 men had higher mean levels of triglycerides (+38 mg/dl) and apolipoprotein B (+11 mg/dl) as well as lower mean levels of high density lipoprotein (HDL) cholesterol (-15 mg/dl) and apolipoprotein A-I (-19 mg/dl). Additionally, men were more overweight, consumed more alcohol, and exercised more frequently than women but were less likely to smoke cigarettes. Controlling for these characteristics, however, did not alter the differences in lipoprotein levels between men and women. In contrast, adjustment for WHR (which was greater among men) reduced the sex differences in levels of apolipoprotein B (by 98%), triglycerides (by 94%), HDL cholesterol (by 33%), and apolipoprotein A-I (by 21%). Similar res...
Thyrotropin-releasing hormone given intrathecally to the rat increases arterial pressure and heart rate.
Authors: KYashpal, SGauthier, J LHenry
Journal: Circulation Research (1989)

In view of evidence implicating thyrotropin-releasing hormone (TRH) as a chemical mediator of synaptic transmission onto spinal sympathetic neurons, this peptide was administered intrathecally, in a dose of 6.5 nmol, at the T9 and T2 spinal levels in the anesthetized rat. At the lower thoracic level TRH increased arterial pressure and heart rate; these effects peaked at 4-7 minutes and decayed over the next 15-20 minutes. At the upper thoracic level the pressor and cardioacceleratory responses were roughly similar in time course but were smaller in magnitude. Hexamethonium (10 mg/kg i.v.) was tested on the responses from the lower thoracic level; both pressor and cardioacceleratory responses persisted after hexamethonium pretreatment. In addition, intravenous administration of 6.5 nmol of TRH failed to alter arterial pressure or heart rate, suggesting that the effects produced by the intrathecal administration of TRH were due to an action of the peptide in the spinal cord. The results also indicate that t...
The Treatment of Hodgkin's Disease.
Authors: V T De Vita, S M Hubbard, D L Longo
Journal: Annals of Internal Medicine (1970)

The available data support the hypothesis proposed by Smithers that Hodgkin's disease appears to be a systemic disorder of the lymphatic system. Standard treatments have been developed that cure approximately 70% of all patients who present to most institutions. Physicians should know the treatment approaches before proceeding with staging, because intelligent use of the best available treatment often obviates the need for staging laparotomy. At present, it is best that either chemotherapy or radiotherapy be used alone, except in patients who have massive mediastinal disease and for whom combinations of radiotherapy and combination chemotherapy are superior. Despite the long series of clinical trials conducted over the past two decades, no combination of four drugs has improved the results obtained with the original mechlorethamine-vincristine-procarbazine-prednisone program, when it is given in sufficient doses. It has been assumed that drug resistance of a specific type was the major reason for treatment failure. Attempts by physicians to overcome drug resistance, using alternating cyclical non-cross-resistant combination chemotherapy, have thus far not proved this approach to be superior to the use of a four-drug combination in full doses, and call into question this approach to testing the Goldie-Coldman hypothesis. Dose intensity has been a poorly controlled variable in virtually all clinical trials in Hodgkin's disease, and inadequate dosing may be the prime reason for treatment failure. This point has been highlighted by recent excellent results with marrow-ablative, high-dose chemotherapy and autologous bone marrow transplantation support for patients with very advanced "drug-resistant" disease. Investigators are now attempting to improve dose intensity by using more concentrated versions of standard drug combinations with colony-stimulating factors for support.
Echocardiographic study of the paradoxical arterial pulse in chronic obstructive lung disease.
Authors: H PSettle, P JEngel, N OFowler, J MAllen, C LVassallo, J NHackworth, R JAdolph, D CEppert
Journal: Circulation (1980)

In nine subjects with chronic obstructive pulmonary disease (COPD) and pulsus paradoxus, M-mode echocardiograms showed inspiratory augmentation of right ventricular dimensions and inspiratory decrease of left ventricular diastolic dimensions. In five subjects in whom the echocardiographic transistor was in the subxiphoid position, mean right ventricular dimensions increased during inspiration from 1.4 +/- 0.20 to 2.96 +/- 0.38 cm (p < 0.01). With inspiration, mean left ventricular diastolic dimensions decreased from 4.8 +/- 0.61 to 3.7 +/- 0.63 cm (p < 0.01) in these five subjects. Two-dimensional echocardiograms, performed in three subjects, confirmed inspiratory augmentation of right ventricular cross-sectional area. Similar changes were produced in two normal volunteers by artificial obstruction to breathing. Left ventricular ejection time measurements demonstrated an inspiratory decline in left ventricular stroke volume. Inspiratory filling of the right ventricle is not hampered, but rather is exagger...
Two levels of resting potential in canine cardiac Purkinje fibers exposed to sodium-free solutions.
Authors: J RWiggins, P FCranefield
Journal: Circulation Research (1976)

Canine cardiac Purkinje fibers exposed to sodium-free solutions containing 16 mM CaCl2, 20 mM tetraethylammonium chloride, 108 mM tetramethylammonium chloride, and 2.7 mM KCl may be quiescent at a resting potential of either -50 mV or -90 mV. The membrane potential of these fibers can be switched from -50 mV to -90 mV by a hyperpolarizing current pulse and from -90 mV to -50 mV by a depolarizing current pulse. The transition from -50 mV to -90 mV depends on a voltage-dependent increase in potassium conductance, that conductance being low at -50 mV and high at -90 mV. A reduction in potassium conductance causes the fiber to depolarize from -90 mV to -50 mV because of the presence of an inward current which apparently is carried mainly by Ca. Fibers that show a high resting potential cannot be excited except by depolarizing stimuli strong enough to move the membrane from -90 mV to a threshold potential of about -40 mV. Fibers that show a low resting potential are more easily excited and may show rhythmic ac...
Effect of acute volume alterations on norepinephrine and dopamine-beta-hydroxylase in normotensive and hypertensive subjects.
Authors: C RLake, M GZiegler
Journal: Circulation (1978)

Fifty-six patients with essential hypertension and 29 normotensive controls were hospitalized and volume expanded with saline or volume depleted with furosemide. We measured plasma norepinephrine (NE) and dopamine-beta-hydroxylase (DBH) to evaluate their sympathetic nervous activity. NE and DBH levels and their response to volume changes were the same in normal and hypertensive subjects. Volume depletion increased plasma NE in recumbent subjects by 50% and in standing subjects by 75% but did not alter DBH. Volume expansion with 2 liters of normal saline did not generally alter plasma NE, but led to a small decrease in DBH. Hypertensives have normal plasma levels of NE and DBH and normal responses of NE and DBH to alterations in volume and posture. The human sympathetic nervous system increases NE output during volume depletion, but fails to decrease NE during volume expansion.