tbuckley/cabot-search huggingface dataset:
A role for endogenous endothelin-1 in neointimal formation after rat carotid artery balloon angioplasty. Protective effects of the novel nonpeptide endothelin receptor antagonist SB 209670.
Authors: S ADouglas, CLouden, L MVickery-Clark, B LStorer, THart, G ZFeuerstein, J DElliott, E HOhlstein
Journal: Circulation Research (1994)

The observation that levels of the mitogenic peptide endothelin-1 are elevated in the human coronary sinus after percutaneous transluminal coronary angioplasty (PTCA) has implicated endothelin-1 in the etiology of vascular restenosis. The present study examined this hypothesis in both an in vitro and an in vivo rat model of neointimal formation by using the novel nonpeptide endothelin receptor antagonist SB 209670. In vitro, endothelin-1 (1 nmol/L) induced a ninefold increase in rat aortic vascular smooth muscle [3H]thymidine incorporation. This endothelin A receptor-mediated effect was completely inhibited by SB 209670 (IC50, 6.2 +/- 2.2 nmol/L). In vivo, acute intra-arterial administration of exogenous endothelin-1 (5 to 500 pmol/kg over a 30-minute period immediately after angioplasty) dose-dependently augmented the degree of neointimal formation (by up to 150% when assessed 14 days after surgery). This response was evident as early as 7 days after angioplasty. Hemodynamic studies indicated that this a...
Dendrimer-decorated nanogels: Efficient nanocarriers for biodistribution in vivo and chemotherapy of ovarian carcinoma
Authors: Xin Li, Zhijun Ouyang, Helin Li, Chaolei Hu, Pabitra Saha, Lingxi Xing, Xiangyang Shi, Andrij Pich
Journal: Bioactive Materials (2021)

Nanomedicine has revolutionized disease theranostics by the accurate diagnosis and efficient therapy. Here, the PAMAM dendrimer decorated PVCL-GMA nanogels (NGs) were developed for favorable biodistribution in vivo and enhanced antitumor efficacy of ovarian carcinoma. By an ingenious design, the NGs with a unique structure that GMA-rich domains were localized on the surface were synthesized via precipitation polymerization. After G2 dendrimer decoration, the overall charge is changed from neutral to positive, and the NGs-G2 display the whole charge nature of positively charged corona and neutral core. Importantly, the unique architecture and charge conversion of NGs-G2 have a profound impact on the biodistribution and drug delivery in vivo. As a consequence of this alteration, the NGs-G2 as nanocarriers emerge the highly sought biodistribution of reduced liver accumulation, enhanced tumor uptake, and promoted drug release, resulting in the significantly augmented antitumor efficacy with low side effects. Remarkably, this finding is contrary to some reported work that the nanocarriers with positive charge have preferential liver uptake. Moreover, the NGs-G2 also displayed thermal/pH dual-responsive behaviors, excellent biocompatibility, improved cellular uptake, and stimuli-responsive drug release. Encouragingly, this work demonstrates a novel insight into the strategy for optimizing design, improving biodistribution and enhancing theranostic efficacy of nanocarriers.
The effects of minoxidil on pulmonary and systemic hemodynamics in hypertensive man.
Authors: P EKlotman, C EGrim, M HWeinberger, W EJudson
Journal: Circulation (1977)

Pulmonary hypertension has been described as a possible complication of the antihypertensive vasodilator, minoxidil. A prospective study was undertaken in seven severely hypertensive patients refractory to multiple drug therapy. Treatment was initiated with fixed doses of hydrochlorothiazide (100 mg/day) and propranolol (160 mg/day) for a control period. Mean systemic arterial pressure, cardiac output, and pulmonary artery pressure were then compared before and after the addition of acute (5 day) and chronic (2 month) therapy with minoxidil. Mean arterial blood pressure decreased from a control value of 135 mm Hg to a value of 104 mm Hg acutely and 108 mm Hg chronically. Significant increases in mean cardiac output occurred with minoxidil therapy (from 4.2 L/min control to 5.4 L/min acutely and 5.1 L/min chronically) despite concomitant propranolol treatment. Mean pulmonary artery pressure did not increase either acutely or chronically. The data suggest that in patients with normal pulmonary hemodynamics ...
The effect of brief vagal stimulation on the isolated rabbit sinus node.
Authors: J FSpear, K DKronhaus, E NMoore, R PKline
Journal: Circulation Research (1979)

We developed an isolated rabbit atrial preparation which responds consistently and reproducibly to brief, submaximal stimulation of the autonomic nerves contained in it. In 6 of 11 preparations in the presence of propranolol (1 mg/liter), the time course of changes in the atrial rate following 120 msec vagal stimulation was bimodal. The maximal slowing occurred at 0.64 +/- 0.16 second, and the peak secondary slowing occurred at 2.3 +/- 1.0 seconds. An acceleratory component occurred between the first and second peaks between 0.8 and 1.6 seconds. The total time course of vagal effect lasted for 5.0 +/- 2.0 seconds. These changes in rate could not be explained by shifts in the location of the primary pacemaker. The acceleratory component was due to a 4.7 +/- 2.0 (SD) mV depolarization of the maximum diastolic membrane potential of the primary pacemaker of the sinus node which lasted for 1.8 +/- 0.3 seconds. Following vagal stimulation, there was an increase of 0.2 mM in the activity of potassium in the extr...
Force-velocity relation and myosin light chain phosphorylation in bovine coronary arterial smooth muscle.
Authors: W CMiller-Hance, K EKamm
Journal: Circulation Research (1991)

We have investigated in bovine left ventricular coronary arteries the relation between the biochemical regulatory event of myosin light chain phosphorylation and the mechanical events of isometric stress and isotonic shortening, under conditions of stimulation by depolarization (65 mM KCl) or receptor occupancy (2 microM 5-hydroxytryptamine [5-HT]). At rest, levels of light chain phosphorylation were 0.07 +/- 0.01 mol phosphate/mol light chain. Maximal values were significantly different for KCl (0.42 +/- 0.02 mol phosphate/mol light chain at 1 minute) and 5-HT stimulation (0.58 +/- 0.01 mol phosphate/mol light chain at 30 seconds). Increases in light chain phosphorylation preceded isometric stress development, and values remained elevated at approximately 0.35 mol phosphate/mol light chain for up to 2 hours with both KCl and 5-HT. The sites of phosphorylation were identical for KCl and 5-HT at 2 hours. Maximal stresses for each stimulus were also maintained for 2 hours. Values of maximum velocity of shor...
Determinants of induced sustained arrhythmias in survivors of out-of-hospital ventricular fibrillation.
Authors: C DSwerdlow, G HBardy, JMcAnulty, JKron, J TLee, EGraham, JPeterson, H LGreene
Journal: Circulation (1987)

We prospectively studied 196 consecutive survivors of out-of-hospital ventricular fibrillation (VF) not associated with acute myocardial infarction and 46 consecutive, control patients without prior ventricular arrhythmias. Programmed stimulation included two extrastimuli (S3 protocol) in all patients and three extrastimuli (S4 protocol) in the last 140 study patients and in all control patients. Sustained ventricular tachycardia (VT) or VF was not induced in any control patient. In study patients, logistic regression identified two independent predictors of induced, sustained VT for both S3 and S4 protocols: prior spontaneous, sustained VT (37 patients; p less than or equal to .001) and prior myocardial infarction (113 patients; p = .005). With the S3 protocol, sustained VT was induced in 54% of patients with both prior myocardial infarction and prior sustained VT vs 4% without either; with the S4 protocol, sustained VT was induced in 91% vs 13%, respectively. Eighty-three percent of induced VT episodes ...
Power output of skeletal muscle ventricles in circulation: short-term studies.
Authors: J DMannion, M AAcker, R LHammond, WFaltemeyer, SDuckett, L WStephenson
Journal: Circulation (1987)

Skeletal muscle ventricles (SMVs) were constructed from preconditioned latissimus dorsi muscles in eight dogs and then connected to each animal's systemic arterial circulation in short-term experiments. The lengths of time that SMVs could produce hemodynamic work as left ventricular assist devices were recorded. After 4 hr of continuous pumping at approximately 55 beats/min, six of eight SMVs were able to generate systolic pressures of 128 +/- 23 mm Hg and flows of 340 +/- 31 ml/min, representing 20 +/- 4% of the animals' cardiac output. After 8 hr of continuous pumping, five of the eight SMVs generated pressures of 110 +/- 15 mm Hg and flows of 308 +/- 88 ml/min, or 15 +/- 7% of the animals' cardiac output. The stroke work produced by the SMVs was intermediate between that of the animals' left and right ventricles. Although the SMVs were stimulated to contract at only about one-third the heart rate, the power output of the SMVs approximated that of the right ventricles because of the greater stroke work ...
Ultrasonic tissue characterization with integrated backscatter. Acute myocardial ischemia, reperfusion, and stunned myocardium in patients.
Authors: M RMilunski, G AMohr, J EPérez, ZVered, K AWear, C JGessler, B ESobel, J GMiller, S AWickline
Journal: Circulation (1989)

We have previously shown in studies of experimental animals that myocardium exhibits a cardiac cycle-dependent variation of integrated backscatter that reflects regional myocardial contractile performance and that is blunted promptly after arterial occlusion and recovers after reperfusion. To define the clinical utility of ultrasonic tissue characterization with integrated backscatter for detection of acute myocardial infarction and reperfusion, 21 patients (14 men and seven women) were studied in the cardiac care unit within the first 24 hours (mean time, 11.3 hours; range, 3.5-23.8 hours) after the onset of symptoms indicative of acute myocardial infarction with conventional two-dimensional and M-mode echocardiography and with analysis of integrated backscatter. The magnitude of cyclic variation of integrated backscatter was measured from several sites within acute infarct regions and normal regions remote from the infarct zone for each patient. The average magnitude of cyclic variation among all patien...
Abnormalities of dynamic ventricular shape change in patients with aortic and mitral valvular regurgitation: assessment by Fourier shape analysis and global geometric indexes.
Authors: D AKass, T ATraill, MKeating, P IAltieri, W LMaughan
Journal: Circulation Research (1988)

The normal cardiac cycle is associated with dynamic changes in left ventricular shape, which can be disturbed in disease states. To assess the influences of diastolic volume, percent ejected volume, and abnormalities of acute or chronic systolic loading on general and detailed chamber geometry, we studied dynamic shape change recorded by x-ray contrast ventriculography in both normal patients and those with aortic (AR) or mitral (MR) valve regurgitation. While both lesions increased diastolic volume, the character of load throughout ejection differed markedly. Detailed cavity geometry was assessed by a Fourier analysis technique and general shape by eccentricity and circularity indexes. Normal hearts, showed increased systolic elongation by all indexes. AR patients displayed a similar rise in eccentricity during ejection; however, the extent of shape change when measured by Fourier and circular indexes was reduced. In contrast, MR patients displayed enhanced systolic shape change, particularly in chamber ...
Proliferation in human gastrointestinal epithelium using bromodeoxyuridine in vivo: data for different sites, proximity to a tumour, and polyposis coli
Authors: Potten, Kellett, Rew, Roberts
Journal: Gut (1992)

The distribution of DNA synthesising cells in the crypts of the epithelium in human small and large bowel after injection of bromodeoxyuridine into patients has been studied in relation to the position of the cells in the crypt using immunohistochemistry. Different sites of normal epithelium have been studied. The ileum has a shorter crypt and a very significantly smaller total cell population size. However, it has similar peak labelling index (LI) values to the colon, while the rectum has a lower peak LI value. The mean position of the label occurs at the 17th cell position in the ileum and at about the 22nd position in both the colon and rectum. The overall mean LI is significantly higher in the ileum at 17.8%, intermediate in the colon at 10.3%, and lowest in the rectum at 8.5%. There is thus an inverse relation between the likelihood of developing a tumour and the rate of cell proliferation as measured by the LI. Assuming a value of 8.6 hours for the duration of S, the data suggest that the cell cycle time in the mid crypt region is about 30 hours for the ileum and colon and about 37 hours for the rectum. Samples taken adjacent (within 1 cm) to a tumour show a general dampening of proliferative activity at all cell positions compared with samples taken more than 5 cm from a tumour.(ABSTRACT TRUNCATED AT 250 WORDS)
Pulmonary vascular effects of hydralazine in a canine preparation of pulmonary thromboembolism.
Authors: JDucas, LGirling, USchick, R MPrewitt
Journal: Circulation (1986)

Pulmonary arterial pressure (PAP)-flow coordinates were obtained in 14 anesthetized dogs before and after pulmonary hypertension was induced with autologous blood clots. Cardiac output (CO) was altered by systemic arteriovenous fistulas. The PAP-CO coordinates were always rectilinear. Before emboli, the mean vascular closing or outflow pressure (the pressure intercept of the PAP-CO line) was 8.8 +/- 2.1 (SD) mm Hg. Emboli increased PAP (15.1 +/- 1.6 to 36.5 +/- 3.5 mm Hg; p less than .001) and decreased CO (3.8 +/- 0.6 to 2.4 +/- 0.8 liters X min-1; p less than .001). Incremental resistance (the slope of the PAP-CO line) only increased slightly. On the other hand, the marked increase in PAP was predominantly due to an increase in effective outflow pressure (from 8.8 +/- 2.1 to 28.6 +/- 3.6; p less than .001). Hydralazine was administered in a dose sufficient to double CO. This did not affect PAP and caused an inconsistent and small decrease in incremental resistance. However, a consistently significant de...
Tidal Volume Ventilation Strategy in ICU Patients Without ARDS—Reply
Authors: Ary Serpa Neto, Fabienne D. Simonis, Marcus J. Schultz
Journal: JAMA (2019)

Our website uses cookies to enhance your experience. By continuing to use our site, or clicking "Continue," you are agreeing to our Cookie Policy | Continue JAMA HomeNew OnlineCurrent IssueFor Authors Podcasts Clinical Reviews Editors' Summary Medical News Author Interviews More Publications JAMA JAMA Network Open JAMA Cardiology JAMA Dermatology JAMA Health Forum JAMA Internal Medicine JAMA Neurology JAMA Oncology JAMA Ophthalmology JAMA Otolaryngology–Head & Neck Surgery JAMA Pediatrics JAMA Psychiatry JAMA Surgery Archives of Neurology & Psychiatry (1919-1959) JN Learning / CMESubscribeJobsInstitutions / LibrariansReprints & Permissions Terms of Use | Privacy Policy | Accessibility Statement 2023 American Medical Association. All Rights Reserved Search All JAMA JAMA Network Open JAMA Cardiology JAMA Dermatology JAMA Forum Archive JAMA Health Forum JAMA Internal Medicine JAMA Neurology JAMA Oncology JAMA Ophthalmology JAMA Otolaryngology–Head & Neck Surgery JAMA Pediatrics JAMA Psychiatry JAMA Surgery Archives of Neurology & Psychiatry Input Search Term Sign In Individual Sign In Sign inCreate an Account Access through your institution Sign In Purchase Options: Buy this article Rent this article Subscribe to the JAMA journal
Altered cardiovascular and neurohumoral responses to head-up tilt after heart-lung transplantation.
Authors: N RBanner, T DWilliams, NPatel, JChalmers, S LLightman, M HYacoub
Journal: Circulation (1990)

Heart-lung transplantation results in afferent and efferent denervation of the transplanted organs including interruption of the central connections from the low-pressure receptors in the atria and pulmonary veins. We investigated whether the cardiovascular and neurohumoral responses to the postural stimulus of head-up tilt were affected after transplantation. Responses in eight heart-lung transplant recipients were studied and compared with those in eight normal subjects matched for age and sex during passive head-up tilt at 45 degrees for 1 hour. The transplant group had a higher initial heart rate (99 +/- 2 versus 68 +/- 2 beats/min, p less than 0.001) and diastolic blood pressure (88 +/- 5 versus 76 +/- 2 mm Hg, p less than 0.05) than did the control group. The increases in heart rate and diastolic blood pressure during head-up tilt were similar in the two groups. Systolic blood pressure remained unchanged. The decrease in cardiac output (30% versus 18%, p less than 0.05) and the increase in systemic ...
Cardiac output-O2 uptake relation during incremental exercise in patients with previous myocardial infarction.
Authors: AKoike, MHiroe, HAdachi, TYajima, HItoh, TTakamoto, KTaniguchi, FMarumo
Journal: Circulation (1992)

BACKGROUNDThe cardiac output-O2 uptake (VO2) relation, which is thought to be linear and predictable in normal humans, has not been clarified in cardiac patients. We evaluated the relation between cardiac output and VO2 during the incremental exercise test in patients with previous myocardial infarction.METHODS AND RESULTSTwenty-two patients (age, 58.1 +/- 8.0 years) with previous myocardial infarction performed a symptom-limited exercise test on a cycle ergometer. VO2 was calculated from the expired gas analysis, and cardiac output was measured by a computerized cadmium telluride detector every 10 seconds during exercise. The ratio of increase in VO2 to the increase in work rate (delta VO2/delta WR) below and above the anaerobic threshold (AT) was 11.1 +/- 3.6 and 11.1 +/- 2.9 ml/min/W, respectively, showing no significant difference. However, the ratio of increase in cardiac output to increase in work rate (delta CO/delta WR) below the AT was 50.1 +/- 26.6 ml/min/W and was significantly decreased to 11....
Quantitative analysis of pulmonary vascular disease in complete transposition of the great arteries.
Authors: SYamaki, FTezuka
Journal: Circulation (1976)

Forty autopsy cases of complete transposition of the great arteries (TGA) and 22 autopsy cases of ventricular septal defect (VSD) were analyzed histologically for evidence of vascular damage due to pulmonary vascular disease (PVD). Positive correlations were generally observed between an index of pulmonary vascular disease (IPVD) and blood pressure of pulmonary circulation. No significant difference in IPVD was found between TGA and VSD in the first five months of life, when cases of each disease were compared at similar blood pressure levels. After that age, however, IPVD was much higher in TGA, and particularly severe PVD in this disease was demonstrated histologically. Morphometrical analysis of the pulmonary artery revealed hypertrophy of the muscular cost in response to elevated blood pressure. However, the progress of medial hypertrophy was retarded in TGA in the first five months, and medial thickness in arteries of cases of TGA older than five months was only 70% of that in VSD at the same blood p...
Hypothermia Therapy after Traumatic Brain Injury in Children
Authors: Kees H Polderman, Stephan A Mayer, David Menon
Journal: New England Journal of Medicine (2008)

To the Editor: Hutchison et al. (June 5 issue)1 report that hypothermia therapy that was initiated within 8 hours after traumatic brain injury and continued for 24 hours did not improve the neurologic outcome in children in their study. However, five meta-analyses of hypothermia therapy in adults with traumatic brain injury showed a reduction of 22 to 39% in the risk of a poor outcome,2 and the differences in two of these studies were significant.3,4 Hypothermic neuroprotection crucially depends on the promptness5 and duration2 of treatment (since brain edema peaks 1 to 4 days after such injury), as well as the speed of rewarming.2,3 In previous studies, a rewarming speed of more than 24 hours and a cooling duration of more than 48 hours were key factors in determining efficacy.2,3 In the study by Hutchison et al., target temperatures were reached after 10.2 hours; patients were rewarmed after 24 hours, regardless of clinical condition and intracranial pressure. Several potential randomization biases were present, which may have accounted for the rates of adverse outcome being close to predicted levels in the hypothermia group (a predicted rate of 30%, as compared with a reported rate of 31%) but much lower in the control group (a predicted rate of 50%, as compared with a reported rate of 22%). More patients in the hypothermia group than in the control group had midline shift, edema, hypotension, and hypoxia, suggesting a greater severity of injury at baseline. Patients in the hypothermia group were also more likely to have hypotension during treatment, despite greater use of vasopressors in this group,1 possibly because of inadequate volume replacement from cold diuresis. Finally, it is unclear how hypothermiainduced electrolyte disorders (specifically, magnesium and phosphorus) were managed.
Trends in Age at Natural Menopause and Reproductive Life Span Among US Women, 1959-2018
Authors: Duke Appiah, Chike C. Nwabuo, Imo A. Ebong, Melissa F. Wellons, Stephen J. Winters
Journal: JAMA (2021)

This national survey study uses the National Health and Nutrition Examination Survey (NHANES) to describe trends in age at natural menopause, age at menarche, and reproductive life span, and variables associated with shorter and longer spans, among US women between 1959-1962 and 2015-2018.
Double-Blind Studies in Dermatology
Authors: William C. Gentry
Journal: JAMA (1973)

<h3>To the Editor.—</h3> Dr. Albert Kligman in the Septemer 24 issue ofThe Journal(225;1658-1659) took issue with our findings (<i>Arch Dermatol</i>107:870-881, 1973) in which we reported a favorable effect of desonide (a new non-fluorinated steroid) from a double-blind study. He labeled the result "spurious." Doctor Kligman is a keen and experienced dermatologist, as well as a seasoned clinical investigator. He is, of course, correct when he points out that the mere fact of a study being done double-blind does not insure the validity of its conclusions. Mild seborrheic dermatitis does respond quickly to even very weak corticosteroid creams, and severe cases of allergic contact dermatitis, such as those induced by poison ivy, do seem to run a course that is influenced only slightly, if at all, by topical corticosteroids. The study in question called for the use of these topical steroids only on dermatoses in which their use