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Biomedical subjects

L M Rivera

Publications and source records attributed to L M Rivera.

At least 19 recordsLinked to original sources
PubMed1999

Improving cancer pain management using a performance improvement framework.

Pain is an important issue in quality of care and is increasingly cited as an outcome used to evaluate effectiveness of nursing care. Research indicates that nurses are not well prepared to care for patients with pain. Thus many patients are inadequately assessed and treated and consequently receive less than optimal pain management. The article describes the development, implementation, and evaluation of a pain education program designed to provide clinical nurses with the knowledge necessary to use appropriate pain management techniques. Program content stresses the use of a performance improvement framework for changing clinical practice in individual clinical settings.

Adult↗
PubMed1997

Blood cell transplantation: its impact on one family.

OBJECTIVES: To share a story about being the wife of a cancer survivor who had a blood cell transplantation (BCT). DATA SOURCES: Personal experience, and published articles related to the impact of cancer on the family. CONCLUSIONS: Cancer affects not only the patient but the entire family unit. Yet, family members are a forgotten population. With advances in cancer treatment, survivorship has increased resulting in caregiving demands that can last for years. The lack of research related to the impact of BCT on family members must be addressed. IMPLICATIONS FOR NURSING PRACTICE: There are many ways that nurses can provide holistic care to family members who have a loved one going through a BCT. Physical, psychological, social, and spiritual aspects of care can make a tremendous impact on the lives of patients and family members.

Adaptation, Psychological↗
PubMed1997

Cancer pain education for patients.

OBJECTIVES: To review the basic principles of patient education, models of innovative approaches to patient education, and needs for future development in patient education. DATA SOURCES: Review articles, research studies, book chapters, personal communication, and standards pertaining to cancer pain education. CONCLUSIONS: Patient education based on principles of effective teaching and learning is the cornerstone of effective pain management. Improved methods of patient teaching combined with novel approaches to delivering appropriate pain content can lead to enhanced patient compliance with the prescribed pain medication regimen. IMPLICATIONS FOR NURSING PRACTICE: Nurses are essential to improving the care of cancer patients in pain by providing patient education as a care component of professional nursing practice. The challenge remains to overcome significant barriers of limited time and resources to achieve these goals.

Curriculum↗
PubMed1995

Anorexia, cachexia, and dysphagia: the symptom experience.

OBJECTIVES: To review the symptoms of anorexia, cachexia, and dysphagia and to provide information on nutritional assessment and interventions. DATA SOURCES: Published studies of anorexia, cachexia, and dysphagia, research abstracts, and review articles. CONCLUSIONS: Anorexia, cachexia, and dysphagia can cause severe alterations in nutrition in cancer patients that may lead to irreversible nutritional compromise and death. Nursing research must focus on symptom management of these three symptoms, the needs of the patient and family, and the impact of dysphagia on quality of life. IMPLICATIONS FOR NURSING PRACTICE: Assessment, objective evaluation, pharmacological interventions, and nutritional counseling are important interventions for patients with anorexia and cachexia. Swallowing therapy, food intake adjustments, oral hygiene, and supportive care are important measures needed by the patient with dysphagia.

Anorexia↗
PubMed1995

Unscheduled readmissions for uncontrolled symptoms. A health care challenge for nurses.

The purpose of this study was to measure the impact of nursing strategies to improve cancer pain management on hospital readmission for uncontrolled pain. Strategies include implementing a pain resource nurse program (PRN), making pain management a focus in the continuous quality improvement process of the institution and creating a supportive care service. Admissions were compared before and after implementation of the strategies. Results for 1989 to 1990 revealed 5772 total admission with 4.4% (255) admissions for uncontrolled pain; results for 1992 to 1993 revealed 4066 total admissions with 3.0% (121) admissions for uncontrolled pain. Findings indicate that strategies were effective in reducing the number of readmissions for uncontrolled pain.

Adolescent↗
PubMed1994

Diagnostic value of fasting plasma peptide concentrations in patients with chronic diarrhea.

To evaluate the utility of screening for multiple gastrointestinal peptides in the evaluation of patients with chronic diarrhea, we studied 193 patients referred for evaluation of chronic diarrhea and eight patients with known peptide-secreting tumors as a reference group. Fasting plasma samples were assayed for motilin, neurotensin, pancreatic polypeptide, somatostatin, substance P, vasoactive intestinal polypeptide, gastrin-releasing peptide, and calcitonin during a protocol evaluation for causes of chronic diarrhea. Although none of the referred patients were found to have tumors, abnormal levels of one or more peptides were found in 86 of 193 patients (45%). Abnormal plasma peptide levels were sometimes as high in these patients as in patients with known peptide-secreting tumors and would have led to mistaken diagnoses of tumors much more often than they would have led to correct diagnoses. The positive predictive value of elevation of any assayed peptide was < 2% at realistic prevalence rates for peptide-secreting tumors; the negative predictive value of a series of normal results was > 99%, but much of this was due to the rarity of these tumors. Patients with chronic diarrhea should not be screened routinely with a panel of plasma peptide assays in an effort to detect tumors; instead, peptide levels should be ordered selectively. Elevated fasting concentrations of the plasma peptides measured in this study are most likely epiphenomena due to diarrhea and should not be the sole basis for invasive diagnostic or surgical management of these patients.

Chronic Disease↗
PubMed1993

Inhibition of EGF-induced vasoconstriction in isolated rabbit aortic rings with the tyrosine kinase inhibitor RG50864.

The tyrosine kinase inhibitor RG50864 attenuated EGF-induced tension development dose-dependently. Similarly, contractions to a phorbolester were affected by 10 microM RG50864. In comparison, vasoconstrictor activities of norepinephrine, endothelin and Bay K 8644 remained unaltered. Western blots using antiphosphotyrosine antibodies, revealed a time-dependent increase in EGF-induced EGF-receptor autophosphorylation as well as tyrosine phosphorylation of a 55 kDalton cytosolic protein. While the extent of EGF-receptor autophosphorylation remained unaltered in the presence of 10 microM RG50864, phosphorylation of the 55 kD band was decreased two-fold. In summary, in rabbit aorta RG50864 is an inhibitor of EGF-induced vasoconstriction; this inhibitory effect does not appear to be mediated through inhibition of EGF-receptor autophosphorylation but may involve a 55 kD cytosolic protein substrate.

Animals↗
PubMed1993

The pain resource nurse training program: a unique approach to pain management.

Adequate pain management is a 24 hr a day responsibility for health-care professionals working with cancer patients. Because nurses spend more time with patients in pain than any other member of the health-care team, they play a central role in pain assessment and pain management. The City of Hope National Medical Center, a clinical cancer center, developed a pain management course for staff nurses entitled "The Pain Resource Nurse (PRN) Training Program." The purpose of this innovative course was to prepare staff nurses to assume an active role in pain management. Twenty-six registered nurses participated in the 40-hr didactic and clinical course. The curriculum included information on pain assessment, pharmacology, nondrug interventions, and cultural, ethical, and psychosocial issues related to pain. After completion of the course, program staff have remained available to the PRNs to provide current information on pain management, and to assist with role implementation and guidance on interfacing with staff. This paper reports on the development, implementation, and 3-mo evaluation of this unique program.

Education↗
PubMed1993

In vitro and in vivo characterization of an A1-selective adenosine agonist, RG14202.

In this report, we demonstrate that the adenosine agonist N-5'-ethyl-N6-(cyclopentyl) adenosine-5'-uronamide (RG14202) is a vasorelaxant in porcine coronary arterial rings (EC50 = 0.37 +/- 0.054 microM; n = 19). This vasorelaxation (VR) occurs despite RG14202 being 275-fold selective for the rat brain A1 receptor. VR in response to RG14202 was attenuated markedly by the nonselective adenosine antagonist CGS15943, whereas 8-cyclopentyl-1,3-dipropylxanthine (DPCPX), a highly selective A1 antagonist, had only a small inhibitory effect. In contrast, the potassium channel blocker glybenclamide attenuated RG14202-induced VR markedly (85-fold), indicating that modulation of potassium channels is likely involved. In carotid arterial rings, RG14202 was approximately 5 times less potent than in the coronary artery, suggesting that this compound may be more selective for the coronary vasculature. In anesthetized rats, i.v. administration of RG14202 caused a significant decrease in mean arterial pressure only at the highest dose (3 micrograms/kg). In comparison, heart rate was decreased dose-dependently with maximal changes at 3 micrograms/kg. Both the depressor and bradycardic responses could be antagonized with CGS15943. RG14202 increased renal, but had no effect on mesenteric or hindquarter vascular resistance. Glybenclamide pretreatment (20 mg/kg) did not significantly alter the effects of RG14202 on heart rate or regional vascular resistances; however, the depressor response to RG14202 was attenuated.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine↗
PubMed1992

In vitro and in vivo interactions of nitrovasodilators and zaprinast, a cGMP-selective phosphodiesterase inhibitor.

We have examined the interaction of zaprinast, a selective inhibitor of cGMP phosphodiesterase, with guanylate cyclase activators on vascular smooth muscle relaxation in vitro and in vivo. Isolated porcine coronary arterial rings precontracted with prostaglandin F2 alpha (PGF2 alpha) were relaxed dose dependently by the guanylate cyclase activators nitroglycerin and nitroprusside, the cGMP phosphodiesterase inhibitor zaprinast and the endothelium-dependent agent bradykinin. A 1 h pretreatment with 0.5 mM nitroglycerin shifted the dose-response curve to nitroglycerin to the right by a factor of 90, reflecting the development of tolerance. The dose-response curve to sodium nitroprusside was also affected, albeit to a much lesser degree (9-fold increase in IC50). Both zaprinast and bradykinin remained unaffected by nitroglycerin pretreatment. A 30 min pretreatment of rings with zaprinast (1 microM) had no effect on nitroglycerin- or nitroprusside-induced relaxation in control rings, but enhanced vasorelaxation to both nitrovasodilators 7- and 2-fold, respectively, in tolerant rings. Similarly, a 30 min pretreatment of rings with 0.1 microM nitroprusside enhanced zaprinast-induced vasorelaxation 4- and 8-fold, respectively, in control and tolerant rings. Similar observations were made in vivo in anesthetized spontaneously hypertensive rats where zaprinast (0.1-3.0 mg/kg i.v.), caused dose-dependent reductions in mean arterial pressure. This effect was enhanced when rats had been pretreated with nitroprusside (1 micrograms/kg per min). In comparison, in zaprinast-pretreated rats the magnitude of depressor responses to nitroprusside (0.5-5.0 micrograms/kg) was not altered, but the duration of hypotensive response to the highest dose of nitroprusside was enhanced by zaprinast. These data demonstrate an enhanced vasodilatory response of nitrocompounds in combination with peak I-selective phosphodiesterase inhibitors.

3',5'-Cyclic-GMP Phosphodiesterases↗
PubMed1992

Demonstration of vasorelaxant activity with an A1-selective adenosine agonist in porcine coronary artery: involvement of potassium channels.

The vasodilator activity of adenosine has been associated with selective stimulation of A2 receptors. In the present study, the vasorelaxant (VR) activity of an A1-selective agonist, CPA (cyclopentyladenosine), was examined in isolated porcine coronary arterial rings precontracted with prostaglandin F2 alpha and compared to the A2-selective agonist DPMA (N6-[2-(3,5-dimethoxyphenyl)-2-(2-methylphenyl)-ethyl] adenosine). DPMA, approximately 13-fold selective for the rat brain A2 receptor, relaxed isolated coronary arterial rings with an EC50 of 0.59 +/- 0.19 microM (n = 23) whereas CPA, 2200-fold selective for the rat brain A1 receptor, was approximately 5-fold less potent with an EC50 of 3.18 +/- 0.6 microM (n = 11). At low concentrations (10-300 nM) CPA caused vasoconstriction, indicative of the A1-selective nature of this agonist. CGS 15943 (100 nM), a nonselective adenosine antagonist, attenuated the VR activity of DPMA and CPA, causing a 9- and 12-fold rightward shift of the dose-response curves, respectively, whereas 8-cyclopentyl-1,3-dipropylxanthine (20 nM), a highly A1-selective blocker, had no such effect. Both adenosine antagonists abolished the vasoconstrictor response of CPA at low concentrations. The contributions of the cyclic GMP pathway to adenosine-induced VR was assessed using an inhibitor of endothelium-dependent relaxing factor (L-nitroarginine). L-nitroarginine had no effect on the EC50 for CPA-induced VR and, marginally, but not significantly, attenuated DPMA effects. Moreover, no elevation in cyclic GMP levels could be observed in tissues stimulated with CPA or DPMA.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine↗
PubMed1991

Protein kinase C and vascular smooth muscle contractility: effects of inhibitors and down-regulation.

We have compared two different methods of attenuating protein kinase C (PKC) activity in vascular smooth muscle. First, the effects of two purported PKC inhibitors, staurosporine (stauro) and H-7 [1-(5-isoquinolinesulfonyl)-2-methylpiperazine dihydrochloride], were examined on contractility of isolated, intact canine femoral artery. In arterial rings stauro was equipotent in relaxing contractions induced by phenylephrine (PE), phorbol-12,13-dibutyrate (PDBu) and KCl (IC50, 0.31 +/- 0.19; 0.35 +/- 0.2; and 0.34 +/- 0.16 microM). H-7, in comparison, was markedly less potent than stauro (IC50, 0.67 +/- 0.2, 2.33 +/- 0.24; and 6.5 +/- 5.5 microM for PE, PDBu and KCl, respectively). Pretreatment of tissues with 1 microM stauro suppressed tension development almost completely when PE and PDBu were the contractile agonists, and partially in K(+)-depolarized rings. H-7, in contrast, had no inhibitory effect on agonist-induced contraction. Neither basal nor K(+)-stimulated calcium influx was affected by 10 microM stauro. Second, prolonged exposure of canine carotid arterial rings to PDBu (1-100 nM for 24 hr), a means of depleting PKC from the tissue, caused dose-dependent attenuation of agonist-induced contractions. Preincubation with 100 nM PDBu caused complete inhibition of tension induced by norepinephrine (NE) and serotonin and partial inhibition of PDBu- and KCl-induced contractions. Lowering the concentration of PDBu during preincubation to 30, 10 or 1 nM reduced markedly the inhibitory effects. The inactive phorbolester 4 alpha-phorbol-12,13-didecanoate (4 alpha-PDD) had no effect on agonist-induced contractions. PKC activity was determined in rings contracted isometrically with PDBu or NE after prolonged exposure to vehicle, 4 alpha-PDD or PDBu.(ABSTRACT TRUNCATED AT 250 WORDS)

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1990

Differential alteration of vascular reactivity in rabbit aorta with modest elevation of serum cholesterol.

The effect of diet-induced, moderate elevation of serum cholesterol on vascular reactivity in isolated rabbit abdominal aortic rings was examined by using a series of vasoconstrictor and vasodilator agonists. Serum cholesterol of rabbits that were fed a cholesterol-free, casein-rich diet for 10 weeks was elevated approximately 4.5-fold compared with values found in control rabbits that were fed standard lab chow (223 +/- 41 versus 51 +/- 5 mg/dl, respectively). Relaxation responses to carbamylcholine chloride and (+/-)-isoproterenol hydrochloride in vessels from hypercholesterolemic rabbits were markedly inhibited in the presence of norepinephrine, prostaglandin F2 alpha, 5-hydroxytryptamine, and angiotensin II but not in the presence of phorbol 12,13-dibutyrate. The depressed vasodilation in hypercholesterolemic vessels appeared to depend on the agonist initiating the contraction. Sodium nitroprusside-induced relaxations were unchanged in rings from hypercholesterolemic rabbits compared with rings from control rabbits for all contractile agonists except KCl. Isolated aortic rings from hypercholesterolemic rabbits exhibited a slight but significantly increased vasoconstrictor sensitivity to 5-hydroxytryptamine and KCl but not to norepinephrine, prostaglandin F2 alpha, angiotensin II, or phorbol 12,13-dibutyrate compared with aortic rings from control rabbits. These results demonstrate that modest elevation of serum cholesterol is sufficient to depress vasodilator and enhance vasoconstrictor responses to certain agonists. Vasodilator effects are impaired to a greater extent by a small increase in serum cholesterol than are responses to vasoconstrictor agonists. It is postulated that the induction of differential alterations in vascular reactivity with moderate increase in serum cholesterol may represent important early events predisposing arteries to vasospasm.

Angiotensin II↗
PubMed1986

Episodic laryngeal dyskinesia. Clinical and psychiatric characterization.

We have obtained physiologic and psychiatric evaluations on five subjects with episodic laryngeal dyskinesia (LD) and compared them with three patients with expiratory laryngeal stridor and asthma (ELS), and five with chronic asthma (CA). Laryngoscopy confirmed adduction of the vocal cords. Diminished inspiratory flow rates with an expiratory/inspiratory ratio of 1.5 to 3.3 was demonstrated by flow volume studies. Flows improved strikingly while breathing an 80 percent helium/20 percent oxygen mixture. Patients with LD showed varying degrees of depression and sought some form of secondary gain. A histrionic personality, conversion or factitious disorders are not an essential part of this syndrome. Tracheostomy may seldom be necessary in the managing of the acute crisis of LD. Reassurance, oxygen, intermittent positive pressure, and sedation may be sufficient. Mildly depressed patients decreased the frequency and severity of wheezing episodes after receiving reassurance and a clear explanation of ventilatory mechanics.

Aged↗
PubMed1982

Postnatal persistence of capillary-venous differences in hematocrit and hemoglobin values in low-birth-weight and term infants.

Full-term and preterm infants were studied to determine whether differences between capillary and venous hematocrit and hemoglobin values were detectable after the first week of life. Significant differences were shown to persist in both term and preterm infants into at least the third postnatal months. However, the differences were considerably greater in low-birth-weight infants, with mean capillary values at ages 4 to 6 postnatal weeks approximately 11% to 12% higher than the corresponding venous values. The data indicated that capillary-venous differences were related not only to postnatal age, but also the postconceptual age.

Capillaries↗
PubMedDate not supplied

Respiratory rate greater than 50 per minute as a clinical indicator of pneumonia in Filipino children with cough.

The diagnosis and epidemiology of acute respiratory tract infection (ARI) in 199 children less than 5 years old were investigated in Manila. As part of this study, children who were treated at one of two outpatient clinics for cough of less than 3 weeks' duration were studied to test the validity of the use of a respiratory rate (RR) of greater than 50/minute for identifying ARI of a severity necessitating treatment with antibiotics. In the first population, in which 69% of the children had radiologically confirmed pneumonia, the sensitivity of a RR of greater than 50/minute was 54%, the specificity was 84%, the false-positive rate was 16%, and the false-negative rate was 46%. In the second population, in which 29% of the children had pneumonia, the sensitivity and positive predictive values were low. The validity of a RR of greater than 50/minute may vary in populations with different prevalences of ARI.

Child, Preschool↗
PubMedDate not supplied

Ethical decision making in oncology: a case study approach.

Every day healthcare professionals are involved in making difficult clinical decisions. This has become more apparent as society changes, in part due to technologic growth and diminishing resources. This article identifies basic principles of bioethics, applies those principles to situations that occur in the process of providing care to oncology patients, and identifies concerns expressed by nurses attending an oncology conference that are related to those patient situations. Bioethical principles are described and include autonomy, beneficence, nonmaleficence, and justice. A decision-making model is provided as a tool to resolve ethical dilemmas.

Adult↗