Discussion of Annotated Research Articles Results in Increases in Scientific Literacy within a Cell Biology Course.

As the amount and complexity of scientific knowledge continues to grow, it is essential to educate scientifically literate citizens who can comprehend the process of science and the implications of technological advances. This is especially important when educating science, technology, engineering, and mathematics (STEM) college students, since they may play a central role in the future of scientific research and its communication. A central part of decoding and interpreting scientific information is the ability to analyze scientific research articles. For this reason, many different approaches for reading scientific research articles have been developed and published. Despite the availability of numerous ways of analyzing scientific research articles, biology students can face challenges that may prevent them from fully comprehending the text. We sought to address student challenges with science vocabulary and content knowledge by adding structural supports to in-classroom article discussions through the use of annotated articles from the Science in the Classroom initiative. We describe the pedagogical approach used for discussing scientific research articles within a required biology course. In this context, we found that students' scientific literacy skills increased at the end of the semester. We also found that, for each article discussed, the majority of students could interpret graphical representations of article results and that they could identify and comprehend components of the experimental design of the study.

Telemedicine in pediatric surgery.

IMPORTANCE: Telemedicine is an emerging strategy for healthcare delivery that has the potential to expand access, optimize efficiency, minimize cost, and enhance patient satisfaction. OBJECTIVE: To review the current spectrum, potential strategies, and implementation process of telemedicine in pediatric surgery. DESIGN: Review and opinion design. SETTING: n/a. PARTICIPANTS: n/a. MAIN OUTCOMES AND MEASURES: n/a. RESULTS: n/a. CONCLUSIONS AND RELEVANCE: Telemedicine is an emerging approach with the potential to facilitate efficient, cost-effective delivery of pediatric surgical services. BRIEF ABSTRACT: Telemedicine is an emerging strategy for healthcare delivery that has the potential to expand access, optimize efficiency, minimize cost, and enhance patient satisfaction. The objectives of this review are to explore common terms in telemedicine, provide an overview of current legislative and billing guidelines, review the current state of telemedicine in surgery and pediatric surgery, and provide basic themes for successful implementation of a pediatric surgical telemedicine program. TYPE OF STUDY: Review. LEVEL OF EVIDENCE: Level V.

Measuring and Advancing Experimental Design Ability in an Introductory Course without Altering Existing Lab Curriculum.

Introductory biology courses provide an important opportunity to prepare students for future courses, yet existing cookbook labs, although important in their own way, fail to provide many of the advantages of semester-long research experiences. Engaging, authentic research experiences aid biology students in meeting many learning goals. Therefore, overlaying a research experience onto the existing lab structure allows faculty to overcome barriers involving curricular change. Here we propose a working model for this overlay design in an introductory biology course and detail a means to conduct this lab with minimal increases in student and faculty workloads. Furthermore, we conducted exploratory factor analysis of the Experimental Design Ability Test (EDAT) and uncovered two latent factors which provide valid means to assess this overlay model's ability to increase advanced experimental design abilities. In a pre-test/post-test design, we demonstrate significant increases in both basic and advanced experimental design abilities in an experimental and comparison group. We measured significantly higher gains in advanced experimental design understanding in students in the experimental group. We believe this overlay model and EDAT factor analysis contribute a novel means to conduct and assess the effectiveness of authentic research experiences in an introductory course without major changes to the course curriculum and with minimal increases in faculty and student workloads.

Age differences in stroop interference in working memory.

Working memory capacity can be conceptualized as the ability to use controlled attention in short term memory (Engle, Tuholski, Laughlin, & Conway, 1999). We tested this idea in young and older adults by combining the task demands of two neuropsychological tests, word span, and Stroop color-naming. Young and older adults were asked to name the colors of a series of congruent and incongruent color-words (between 2 and 6 words/trial). After all the color-words were presented participants attempted to recall the colors in their serial order. This task required inhibition of the prepotent word reading response (i.e., color naming), with a concurrent memory load (caused by the need to maintain already named colors in short-term memory). Older adults showed greater interference effects, and these interference effects increased as a function of memory load. Regression analyses showed that measures of working memory capacity and executive function accounted for unique variance in incongruent color-word errors for older adults. Defining working memory capacity as the ability to use controlled attention in short-term memory may be a fruitful way to think about this concept in studies of executive function.

Development of a Position Sensitive Neutron Detector with High Efficiency and Energy Resolution for Use at High-Flux Beam Sources.

We are developing a high-efficiency neutron detector with 1 cm position resolution and coarse energy resolution for use at high-flux neutron source facilities currently proposed or under construction. The detector concept integrates a segmented (3)He ionization chamber with the position sensitive, charged particle collection methods of a MicroMegas detector. Neutron absorption on the helium produces protons and tritons that ionize the fill gas. The charge is amplified in the field region around a wire mesh and subsequently detected in current mode by wire strips mounted on a substrate. One module consisting of a high-voltage plate, a field-shaping high-voltage plate, a grid and wire strips defines a detection region. For 100 % efficiency, detector modules are consecutively placed along the beam axis. Analysis over several regions with alternating wire strip orientation provides a two-dimensional beam profile. By using (3)He, a 1/v absorption gas, each axial region captures neutrons of a different energy range, providing an energy-sensitive detection scheme especially useful at continuous beam sources.

Item-specific processing reduces false memories.

We examined the effect of item-specific and relational encoding instructions on false recognition in two experiments in which the DRM paradigm was used (Deese, 1959; Roediger & McDermott, 1995). Type of encoding (item-specific or relational) was manipulated between subjects in Experiment 1 and within subjects in Experiment 2. Decision-based explanations (e.g., the distinctiveness heuristic) predict reductions in false recognition in between-subjects designs, but not in within-subjects designs, because they are conceptualized as global shifts in decision criteria. Memory-based explanations predict reductions in false recognition in both designs, resulting from enhanced recollection of item-specific details. False recognition was reduced following item-specific encoding instructions in both experiments, favoring a memory-based explanation. These results suggest that providing unique cues for the retrieval of individual studied items results in enhanced discrimination between those studied items and critical lures. Conversely, enhancing the similarity of studied items results in poor discrimination among items within a particular list theme. These results are discussed in terms of the item-specific/ relational framework (Hunt & McDaniel, 1993).

Direct pharmacologic and osmolal effects of contrast media on the mechanics of heart muscle isolated from cats.

We studied 56 right ventricular papillary muscles isolated from cats to determine whether the direct mechanical effects of contrast media are due to their pharmacologic action or to the hyperosmolality caused by them. A 10% solution of Renografin-76 abruptly decreased force 22% below control, then slowly increased it to 22% above control. To elucidate these changes we also studied: (1) Renografin-60 (lower concentration of diatrizoate); (2) meglumine and diatrizoate; (3) meglumine alone; (4) diatrizoate sodium; (5) ethylene diamine tetra-acetic acid (EDTA) (same concentration as in Renografin-76); (6) sucrose to increase osmolality; and (7) Amipaque (metrizamide), a contrast medium without meglumine or diatrizoate. All solutions containing meglumine, and EDTA alone decreased force. Diatrizoate sodium also decreased force initially, presumably due to the high sodium concentration. Meglumine alone decreased force abruptly and substantially. In contrast, metrizamide and 100 mmol sucrose only increased force. Thus, the abrupt decrease in force was caused by the pharmacologic action of meglumine, EDTA, or high sodium in the contrast media, whereas the slow increase in force was caused by hyperosmolality.

Nonuniformity of contraction and relaxation of mammalian cardiac muscle.

Nonuniformity of contraction and relaxation in cardiac muscle results from relaxation asynchronies between segments in the central region and their interaction with the prevailing loading conditions, and this may reflect regional differences in activation or force potential at a given time during a twitch.

Comparative force-velocity relation and analyses of myosin of dog atria and ventricles.

The isolated muscle and purified myofibrillar proteins of canine atria and ventricles were compared relative to force-velocity relations and rate of adenosine 5'-triphosphatase (ATPase) activity as a function of calcium concentrations. The maximal stress development of isolated trabeculae of canine atria was similar to that of canine right ventricular papillary muscles when analyzed at saturating calcium concentrations (7.5 mM); however, stress was less in the atria when studied at normal calcium concentrations (2.5 mM). The maximal velocity of shortening of atrial trabeculae was about 2.3 times higher than that of ventricular muscle. Regulated actomyosin characterized from the myofibrillar proteins of the two tissues gave directionally similar calcium sensitivity. The maximum velocity of shortening for actin-activated atrial myosin of the dog was approximately 1.8 times higher when the latter was analyzed as a function of actin concentration. Both maximal tension of isolated muscle and regulated actomyosin ATPase activity were dependent on calcium concentration.

Vasodilator and inotropic effects of the antiarrhythmic drug melperone.

We investigated the hemodynamic and inotropic effects of the new class III antiarrhythmic drug melperone. In eight pentobarbital-anesthetized dogs, the effects of intravenous melperone 0.5, 2.5, and 12.5 mg/kg-1 were tested. During atrial pacing we measured cardiac output (CO), mean aortic blood pressure (MAP), right (RV) and left (LV) ventricular pressures, and LV dP/dt. In six RV papillary muscles isolated from cats and suspended in a muscle bath containing Krebs-Henseleit solution, we studied the direct effects of melperone 10(8)-5 X 10(-5) M. Administration of melperone decreased total peripheral resistance, MAP, RV and LV systolic and end-diastolic pressures, while CO remained unchanged. Melperone increased LV dP/dtmax. The contractile force (F) and dF/dtmax of the isolated ventricular muscle preparations increased slightly with increasing concentrations of melperone, up to 10(-5) M. In conclusion, melperone has vasodilator and slight positive inotropic effects in addition to its class III antiarrhythmic effect.

Verapamil preserves myocardial contractility in the hereditary cardiomyopathy of the Syrian hamster.

We attempted to alter the inherited myocardial damage and loss of contractility of the cardiomyopathic Syrian hamster (strain U-MX7-1) by giving cardiac drugs that altered intracellular calcium and myocardial workload. Thirty-seven 21-day-old cardiomyopathic and thirty-seven 21-day-old normal hamsters were divided into five groups each: verapamil-, propranolol-, digoxin-, hydralazine-, and saline-injected. On their 90th day of life, the hamsters were killed. Of the five cardiomyopathic groups, only verapamil reduced myocardial damage. When both "control" and cardiomyopathic hamsters were treated with saline, digoxin, or propranolol, the cardiomyopathic hamsters had significantly less contractile force, maximal rate of force development, and maximum velocity of unloaded shortening. When both groups were treated with verapamil or hydralazine, there were no significant group differences in the indices of contractility. However, when saline-treated cardiomyopathic hamsters were compared with drug-treated cardiomyopathic hamsters, only verapamil preserved myocardial contractility. There was also a weak correlation between the Vmax and the actin-activated ATPase activity of the cardiomyopathic hamsters (r = 0.63, P less than 0.001). We conclude that verapamil helped protect the myocardium of genetically cardiomyopathic hamsters against structural damage, and helped preserve myocardial contractility.

Hemodynamic effects of prazosin in chronic heart failure.

Three series of investigations were carried out with prazosin (PZN) hydrochloride. In the first, hemodynamic effects of PZN were compared with those of hydralazine (HDZ) in 11 patients with chronic congestive heart failure (CHF). In doses up to 5 mg, PZN increased cardiac output (CO) 20% accompanied by a 20% decrease in pulmonary capillary wedge pressure (LVFP). HDZ increased CO by 50% with little or no effect on LVFP. An additional 12 patients were given multiple 5 mg doses of PZN at 6-hour intervals with measurements of hemodynamic and plasma blood levels. Results suggested an attenuation of the effects of PZN on increasing CO but not on decreasing LVFP. This attenuation of CO was not due to inadequate plasma levels. Acute exercise studies (supine bicycle) were performed in 10 patients with severe CHF before and after the administration of several doses of PZN. There appeared to be a greater effect of PZN during exercise than at rest, with a beneficial increase in CO and reduction in LVFP. These data suggest that, despite hemodynamic attenuation of its effects on CO at rest, PZN may still be beneficial to active patients with CHF. In vitro studies with various vasodilators were performed to evaluate potential intropic effects. Isometric force (cat papillary muscle) increased 2% with 10-4M and 31% with 10-3M HDZ. PZN increased force 4% at 10-6M and 18% at 10-4M. Captopril did not increase force development at any dose level. The doses of HDZ and PZN that increased force development were higher than usual clinical doses.

Caffeine reversal of length-dependent changes in myocardial contractile state in the cat.

The present study evaluated potential mechanisms for the slow length-dependent change in myocardial contractile state. Using 40 isolated right ventricular cat papillary muscles, we found that 10 mM caffeine reversed the subsequent slow change in myocardial performance following a change in muscle length. Since caffeine acts both at the sarcolemma and the sarcoplasmic reticulum, we attenuated the sarcolemmal influx of calcium with verapamil, manganese, and low external calcium concentration. None of these interventions altered the caffeine reversal of the length-dependent effect. It thus appears that the length-dependent alteration of contractile state is of intracellular origin, and probably related to altered calcium handling by the sarcoplasmic reticulum.

Nature of load dependence of relaxation in cardiac muscle.

Relaxation of spontaneously contracting single rat cardiac cells with an effective sarcoplasmic reticulum was shown to be sensitive to load, as previously described for intact mammalian ventricular cardiac muscle. Caffeine and tetanic stimulation could modify load-dependent relaxation in intact papillary muscle from cat or rat into a load-insensitive relaxation. Although such load dependence was demonstrated to be normally absent in frog ventricular cardiac muscle, in the present study it could also be made moderately manifest under specific conditions, e.g., high calcium, low sodium, or ouabain. The appearance of load dependence during relaxation in cardiac muscle thus emphasizes the presence of an effective sarcoplasmic reticulum.

Acute changes in the diastolic pressure-volume relationship of the left ventricle.

Acute changes in the diastolic pressure-volume relationship of the left ventricle. Europ. J. Cardiol., 4/Suppl., 105-120. The present study was designed to investigate acute changes in the passive length-tension relations of isolated heart muscle and acute alterations of the left ventricular diastolic pressure-volume relationship of patients. In isolated heart muscle a constant lengthening and shortening technique with computer curve fitting was used to characterize the entire passive length-tension relation. There was no change in passive elastivity following an increase in stimulation frequency or an increase in muscle stretching rate. During the transition from stimulated to nonstimulated contractions, there was a shift to the left in the passive length-tension relation, with a shorter muscle length at the same resting force. In 10 patients undergoing revascularization for preinfarction angina, 7 patients showed a significantly reduced left ventricular enddiastolic pressure at the same enddiastolic volume, together with an improvement in postoperative ejection fraction. In 6 patients who experienced a perioperative myocardial infarction, variable changes in the pressure volume relationship occurred. These presumably reflected the opposite effects of stiffening of infarcted muscle and cardiac dilatation secondary to heart failure. 26 patients with chronic coronary artery disease had ventriculograms before and after 0.4 mg sublingual nitroglycerin. 9 patients showed a significant shift downwards in their pressure-volume relation, with a decreased enddiastolic pressure at the same volume. 2 showed a shift upwards, while the remaining patients showed no measurable change. It is proposed that this latter shift in pressure-volume relationships is due to hemodynamic factors rather than to intrinsic changes in muscle stiffness. Theoretical calculations utilizing A SIMPLIFIED SPHERICAL MODEL of the ventricle suggest that the magnitude of the changes observed cannot be explained by stiffening of the muscle alone and is therefore probably due to hemodynamic factors.

Positive inotropic effects of methoxamine: evidence for alpha-adrenergic receptors in ventricular myocardium.

The present study was undertaken to evaluate the effects of methoxamine on force development and adenyl cyclase activity in cat ventricular myocardium. Methoxamine produced a dose-related increase in force development of isometrically contracting cat papillary muscles. The positive inotropic effects of methoxamine were not altered by beta-adrenergic blockade (propranolol), or catecholamine depletion by prior reserpinization, but were completely prevented by alpha-adrenergic blockade (phentolamine or ergotamine). Neither ergotamine, phentolamine, nor methoxamine had any direct effects on adenyl cyclase activity. Phentolamine did not attenuate the increase in force development produced by paired electrical stimulation, suggesting that it does not block the entry of calcium into the muscle. In summary, methoxamine produced a dose-related increase in force development of the cat papillary muscle that was selectively blocked by alpha-adrenergic receptors in ventricular myocardium.

Comparative evaluation of the specificity and sensitivity of isometric indices of contractility.

It is generally held that a useful mechanical index of contractility is one that is unchanged by changes in initial muscle length, but that changes in appropriate direction and magnitude with a change in contractile state. A number of isometric indices were measured in vitro in isolated cat papillary muscles to quantitate their relative dependence on initial muscle length and contractile state. Results indicate that no one isometric index completely fulfills the definition of an ideal index of contractile state. In particular, indices that change considerably with alterations in contractile state (e.g., maximum dF/dt) are also moderately dependent on preload. Conversely, indices that are moderately insensitive to changes in contractile state (e.g., time-to-peak force) are also insensitive to changes in contractile state. Changes in extrapolated maximum velocity and peak VCE were similar and were less sensitive to changes in contractile state than maximum dF/dt. The most sensitive in vitro index of contractility appears to be maximum dF/dt at a constant preload.