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Biomedical subjects

C B Yucha

Publications and source records attributed to C B Yucha.

At least 19 recordsLinked to original sources

Cerebral palsy: a comprehensive review.

Cerebral palsy is a broad range of static, nonprogressive motor disabilities that present from birth or early childhood as a result of injury to neuromotor components of the central nervous system. Motor performance is normally coordinated via communication between the cerebral cortex, thalamus, basal ganglia, brain stem, cerebellum, spinal cord, and communicating sensori-motor pathways. This complex network lends itself to injury at many different levels. Etiologies are numerous and can occur during the prenatal, perinatal, and postnatal periods. The severity of the neurologic deficit and the clinical manifestations are varied depending on the time, location and nature of the original injury. In order to approach cerebral palsy systematically, the primary health care practitioner must be prepared to recognize neuromotor deficits, diagnose and classify the type of disorder, and implement a methodical treatment plan. The purpose of this article is to review the etiology, pathophysiology, diagnostic classification (Swedish system), clinical manifestations, and therapeutic management of cerebral palsy and prepare the advanced practice nurse to care for the individual and family.

Cerebral Palsy

Interactive distance education: improvisation helps bridge the gap.

In this paper, distance learning through the use of interactive duplex video and audio will be described. The major advantage of this technology is the ability to provide live, face-to-face educational access to distant or isolated students. Yet faculty are concerned about the interrelationships between the instructor and the student and among students in the distance education environment. Improvisation techniques force active participation by the students and can be used to bridge the distance.

Audiovisual Aids

Understanding physiology by acting out concepts.

Typically, classes in anatomy and physiology are taught via lecture and visual aids. This seems to work well for students who are primarily auditory and visual learners but not for those who learn better through kinesthetic experiences. This is the first report describing the use of improvisation to act out physiological concepts within an anatomy and physiology course. Improvisational techniques encourage active participation and allow students to personally interact with and experience difficult concepts in the classroom. In this paper, sensory modality preferences for learning will be discussed briefly. Improvisational techniques will be described, and examples of improvisations useful to convey intricate physiological concepts will be provided. Last, student responses to the use of improvisational techniques in an anatomy and physiology course will be reported.

Acting Out

Calcium and phosphorus derangements.

Derangements in plasma calcium and phosphorus concentrations can precipitate serious and life-threatening complications in critically ill patients. An understanding of the function and homeostasis of these ions is essential to fully comprehend the causes, clinical manifestations, and treatment of calcium and phosphorus imbalances. This article will help the critical care nurse to identify patients at risk, to recognize derangements early (while they are still mild), and to seek and monitor appropriate treatment.

Calcium Metabolism Disorders

Magnesium: homeostasis, imbalances, and therapeutic uses.

Magnesium plays a critical role in numerous metabolic functions, including all reactions involving adenosine triphosphate, and is thus essential for the production and use of energy. Magnesium imbalances are common in hospitalized patients, with magnesium deficiency occurring in 20% to 65% of critically ill patients. This article details the homeostatic mechanisms regulating magnesium, the functions of magnesium, and the causes, manifestations, and treatment of both hyper- and hypomagnesemia. Indications and guidelines for the therapeutic uses of magnesium are also reviewed.

Homeostasis

Multiple organ failure syndrome.

Although many new areas of research are directed at the regulatory aspects of the metabolic response, the prognosis of MOF remains poor. Critical care nurses, challenged to provide a supportive environment during this life-threatening syndrome, must understand its onset, clinical patterns, and prolonged support required by patients. Such knowledge will enable critical care nurses to detect subtle changes while monitoring clinical status, and facilitate timely interventions in order to decrease the morbidity and mortality associated with MOF.

Critical Care

Effect of warm and cold applications on the resolution of i.v. infiltrations.

Differences in pain intensity, surface area measurements of induration and erythema, and interstitial fluid volume when warm versus cold applications were randomly made to an intentional intravenous infiltrate of 5 mL of a designated solution were examined. Three solutions were used: 1/2 saline (154 mOsm), normal saline (308 mOsm), and 3% saline (1027 mOsm). Differences in volume were determined by magnetic resonance imaging (MRI) at three intervals postinfiltration. The sample was 18 healthy adults between 20 and 45 years. There was no difference in remaining infiltrate when 1/2 saline or normal saline were used, but a significant (p < .001) difference was found with 3% saline. For all solutions there was a significant (p < .001) difference in the volume of infiltrate remaining when warmth was applied and this effect held across MRI readings and solutions. Pain intensity did not differ by treatment but a significant (p < .005) difference was found by solution, with 3% saline producing the greatest difference. Erythema was absent with all solutions. Surface induration was affected by solution and decreased over time (p = .001). There was no effect of warmth or cold on surface area induration.

Adult

Renal physiology series: Part 5b of 8. Renal control of phosphorus and magnesium.

The kidney plays a major role in the maintenance of phosphorus and magnesium balance. The homeostasis of these substances is complex and also involves the gastrointestinal tract and the bone. This article reviews the functions, homeostasis, and renal handling and regulation of phosphorus and magnesium. The major sites of tubular reabsorption and the presumed cellular mechanisms involved are described.

Homeostasis

Renal physiology series: Part 5a of 8. Renal control of calcium.

Calcium is critical for many metabolic functions. While 99% of body calcium is found as part of the structure of bone and teeth, 1% found in plasma and body cells is crucial for such functions as blood clotting, nerve impulse conduction, and muscle contraction. The homeostasis of calcium is complex because the gastrointestinal tract, the bones, and the kidneys all affect calcium balance. This article reviews the functions, homeostasis, and renal handling and regulation of calcium. The major sites of renal tubular reabsorption and the presumed cellular mechanisms involved are described.

Calcitonin

Effects of sodium intake, furosemide, and infusion of atrial natriuretic peptide on the urinary and metabolic clearances of arginine vasopressin in normal subjects.

Arginine vasopressin (AVP) and atrial natriuretic peptide (ANP) have important influences on water and electrolyte metabolism, and studies on the interactions between these hormones may have important implications. We have investigated the effects of sodium intake, furosemide, and infusion of ANP on the urinary and metabolic (nonurinary) clearances of AVP in hydrated normal subjects. On a high sodium diet there was an increase in urine volume, sodium excretion, osmolal clearance, plasma ANP concentration, and urinary clearance and fractional excretion of AVP, with a decrease in PRA. The infusion of furosemide increased urine volume, sodium excretion, osmolal clearance, and PRA, but decreased circulating ANP levels and urinary clearance and fractional excretion of AVP. Since there was a positive correlation between circulating ANP and urinary clearance of AVP in these experiments, we infused human alpha ANP in physiological amounts and found increases in the urinary and metabolic (nonurinary) clearances of AVP. The changes in urinary clearance of AVP in all three experiments occurred even in relation to creatinine clearance. These observations demonstrate that urinary clearance of AVP does not correlate with urine volume, sodium or solute excretion, or PRA. The observations support a physiological role for ANP in modulating the renal action of AVP, probably at the level of the renal tubules, and indicate a need for caution when using plasma or urinary AVP as an indicator of AVP release from the neurohypophysis.

Adult

Bicarbonate transport by initial collecting tubule of aquatic- and land-phase amphibia.

The rate of bicarbonate reabsorption (JHCO3) by in vitro initial collecting tubules (ICT) from aquatic- and land-phase Ambystoma tigrinum was measured. These animals intrinsically have different levels of plasma bicarbonate, 17.6 and 27.1 mM, respectively. ICT from both phases reabsorbed bicarbonate at 11 pmol X mm-1 X min-1 when perfused in solutions equilibrated with 3% CO2. The induction of metabolic acidosis or alkalosis had no effect on JHCO3 by in vitro ICT. JHCO3 was abolished when ICT from aquatic animals were perfused with solutions equilibrated with 1% CO2 and returned toward the control value when 3% CO2 was reintroduced. The effect of plasma CO2 partial pressure on JHCO3 of the ICT may explain, at least in part, the observed difference in plasma bicarbonate of the aquatic- and land-phase animals. JHCO3 was reduced to 22% of control with amiloride and to 42% of control when a Na+-free perfusate was used, but was insensitive to ethoxzolamide. These data are consistent with the presence of a sodium-proton exchanger on the apical membrane and a carbonic anhydrase-independent mechanism of H+ secretion.

Absorption

Bicarbonate transport by amphibian nephron.

To determine the site of bicarbonate reabsorption, tubular fragments from five different segments of the salamander nephron (Ambystoma) were perfused in vitro. Bicarbonate contents (total CO2) of tubular fluid were determined by microcalorimetry. Bicarbonate was not transported by the diluting segment or the mid-distal tubule. Although proximal tubule fragments did appear to reabsorb bicarbonate (10.8 +/- 3.7 pmol X mm-1 X min-1, P less than 0.01, n = 14), the chemical gradients observed were small with respect to the sensitivity of our methods. In the late distal tubule (LDT), bicarbonate reabsorption averaged 28.9 +/- 8.2 pmol X mm-1 X min-1 (P less than 0.01, n = 16). Transport in this segment was inhibited by ethoxzolamide or by perfusing with a sodium-free solution. Ethoxzolamide had no effect on the trans-epithelial voltage. Thus bicarbonate is reabsorbed by the LDT of amphibia via a mechanism that is dependent on carbonic anhydrase and the presence of luminal sodium. The 13 initial collecting tubules (ICT) studied did not appear to reabsorb bicarbonate. On the other hand, some ICT developed substantial bicarbonate gradients. Therefore this nephron segment has the capacity to reabsorb bicarbonate.

Ambystoma

Effect of elevation on intravenous extravasations.

Nursing interventions used to treat intravenous extravasations (infiltrations) generally include application of warmth or cold, elevation, and no treatment. In this article, the effect of elevation on infiltrations of 0.45% sodium chloride and 3% saline made intentionally into healthy volunteers is reported. Elevation had no effect on pain, surface area of induration, or volume of infiltrate remaining as quantified by magnetic resonance imaging. A comparison of these data with previously published findings concerning the effect of warmth versus cold on infiltrations shows that no one treatment is better overall in decreasing the symptoms or speeding re-absorption of the infiltrate.

Cryotherapy

Differences among intravenous extravasations using four common solutions.

A frequent complication of intravenous therapy is extravasation (infiltration) of the infused fluid into the interstitial tissues. This study compares infiltrates intentionally made using different IV solutions regarding surface assessment and the volume of infiltrate as quantified by magnetic resonance imaging. Solutions differed significantly concerning pain, surface area of induration, and volume at the site of infiltration.

Adolescent

The minimum discard volume: accurate analysis of peripheral hematocrit.

The purpose of this research is to quantify the minimum amount of blood that must be discarded from an indwelling peripheral intravenous catheter (deadspace 0.5 ml) to obtain an accurate hematocrit reading. Repeat blood sampling from nine subjects is used to develop a mathematical model (Michaelis-Menten curve) describing the mixing of the flush solution and the blood. This model is used to estimate the hematocrit when different volumes are discarded. Differences between the computed hematocrit and true hematocrit were determined for each subject. When 1.5 ml (three times the deadspace volume) is discarded, the 95% confidence interval is within 0.6% of the true hematocrit.

Adult

Detecting i.v. infiltrations using a Venoscope.

This research evaluates the Venoscope for its ability to detect infiltrations when present (sensitivity) and to detect the absence of infiltrations when not present (specificity), and compares these findings with those obtained via ultrasonography. Health adult volunteers were randomly assigned to receive or not receive an intentionally made 5-ml normal-saline infiltration. The Venoscope had a sensitivity of .92-.93 and a specificity of .89-1.0. Ultrasound had a sensitivity of .92-.93 and a specificity of .22-.25. The Venoscope, which is simple and easy to use, is a valid indicator of the presence and absence of i.v. infiltrations.

Adolescent