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Biomedical subjects

R C Beckerman

Publications and source records attributed to R C Beckerman.

At least 19 recordsLinked to original sources
PubMed2000

Differential cardiorespiratory effects of endomorphin 1, endomorphin 2, DAMGO, and morphine.

The novel endogenous mu-opioid receptor (MOR) agonists endomorphin 1 (EM1) and 2 (EM2) were tested for their cardiorespiratory effects in conscious, freely behaving rats. After systemic (intravenous) administration of EM1, EM2, or the selective MOR agonist DAMGO, analgesia, minute ventilation (V E), heart rate (HR) and mean arterial blood pressure (BP) were measured. The threshold dose for analgesia was similar for all 3 peptides ( approximately 900 nmol/kg). All 3 compounds elicited biphasic V E responses, with marked, short-lived V E depressions (4-6 s) followed by more sustained V E increases (10-12 min). However, compared with responses elicited by EM2 or DAMGO, EM1 decreased V E only at higher doses, and produced greater V E stimulation. Morphine produced a V E decrease, but no subsequent V E increase. EM2 and DAMGO decreased HR and BP, while EM1 decreased HR, but did not decrease BP in conscious rats at doses up to 9,600 nmol/kg. In anesthetized rats, all 3 peptides decreased HR and BP. The decreases in V E, HR, and BP were blocked by the MOR antagonist, naloxone HCI (NIx). Only the HR and BP responses, however, were blocked by naloxone-methiodide (MeNIx), indicating central mediation of V E responses and peripheral mediation of cardiovascular responses. We conclude that MOR-selective compounds vary in their cardiorespiratory response characteristics which could be linked to differential cellular actions. The results support the concept that the analgesic, respiratory, and cardiovascular effects of MOR agonists can be dissociated and that EM1-like compounds could provide the basis for novel, safer analgesics.

Analgesics, Opioid↗
PubMed1999

Pulmonary risk factors compromising postoperative recovery after surgical repair for congenital heart disease.

STUDY OBJECTIVES: To identify pulmonary risk factors associated with prolonged ICU stay in young children (< or = 2 years) undergoing surgical repair for congenital heart disease (CHD). DESIGN: Retrospective case series analysis. SETTING: Tertiary-care facility. PATIENTS: Clinical records of 134 consecutive patients aged < or = 2 years undergoing cardiac surgery for CHD were reviewed, and 37 were excluded according to inclusion criteria. Thus, 97 patients were allocated to two groups based on the duration of ICU stay: < or = 7 days (group 1, n = 57), and > 7 days (group 2, n = 40). RESULTS: Mean ICU duration for groups 1 and 2 was 3.0 +/- 0.4 days and 28.1 +/- 4.4 days, respectively (p < 0.001). In group 1, there were three extubation failures, whereas 41 extubation failures occurred in group 2 (p < 0.0001). A total of 22 patients (4 in group 1 and 18 in group 2) developed noninfectious pulmonary complications, such as airway problems, including extrinsic airway compression and tracheobronchomalacia (n = 6); pulmonary hypertension (n = 5); phrenic nerve palsy (n = 7); and pleural effusion (n = 8). These 22 patients (23%) contributed to the majority of total ventilator days (67%) as well as ICU stay (61%). CONCLUSIONS: Pulmonary complications in general, and central airway problems in particular, are a frequent cause for delayed recovery following cardiac surgery in young children.

Cardiac Surgical Procedures↗
PubMed1998

Young inner-city children visiting the emergency room (ER) for asthma: risk factors and chronic care behaviors.

Inner-city children visiting emergency rooms (ER) for asthma often rely on the ER as their primary source of care. To evaluate chronic asthma control, structured interviews were conducted with the adult accompanying a sample of 46 children, 2-6 years old, presenting to an inner-city pediatric ER for asthma. Fifty-one percent had 10 or more prior ER visits and 46% had 2 or more previous hospitalizations. Seventy-two percent had functional severity scores in the moderate to severe range. Only 11% used daily inhaled anti-inflammatory medication. Not one patient had a written self-management plan. Most young children visiting an inner-city ER for asthma have poorly controlled and poorly managed chronic asthma.

Albuterol↗
PubMed1996

Heterozygous alpha 1-antitrypsin deficiency (PiSZ) in an adolescent with asthma.

Although alpha 1-antitrypsin deficiency has been associated with obstructive lung disease in individuals possessing a homozygous phenotype (PiZZ), this association has not been as clearly documented in heterozygous individuals (PiMZ, PiMS, and PiSZ phenotypes). Information regarding the heterozygous adolescent population is particularly lacking, making the evaluation and treatment of such patients difficult. We present the case of an adolescent with a history of asthma and heterozygous (PiSZ) alpha 1-antitrypsin deficiency and outline our management with reference to appropriate literature.

Adolescent↗
PubMed1995

Use of nasal continuous positive airway pressure as treatment of childhood obstructive sleep apnea.

OBJECTIVE: To determine the safety and efficacy of nasal continuous positive airway pressure (CPAP) for obstructive sleep apnea (OSA) during childhood and the effects of growth and maturation on CPAP requirements. DESIGN: Retrospective study with use of a written questionnaire administered to pediatric practitioners treating sleep disorders. SETTING: Nine academic pediatric sleep disorders centers. RESULTS: Data were obtained for 94 patients. Three percent of patients receiving CPAP were less than 1 year, 29% were 1 to 5 years, 36% were 6 to 12 years, and 32% were 13 to 19 years of age; 64% were boys. The longest duration of CPAP use was 4 years. Indications for CPAP included OSA associated with obesity (27%), craniofacial anomalies (25%), idiopathic OSA persisting after adenoidectomy and tonsillectomy (17%), and trisomy 21 (13%). Continuous positive airway pressure was effective in 81 patients (86%), in one patient it was unsuccessful, and in 12 patients compliance was inadequate. The median pressure required was 8 cm H2O (range, 4 to 20 cm H2O); pressure requirements were independent of age or diagnosis. Twenty-two percent of patients eventually required a modification of CPAP levels. Complications of CPAP were minor. Sixty-four percent of centers reported difficulty in obtaining funding for CPAP. CONCLUSIONS: Continuous positive airway pressure is safe, effective, and well tolerated by children and adolescents with OSA. Experience in infants is limited. As pressure requirements change with patient growth, we recommend that CPAP requirements be regularly reevaluated over time. The marked center-to-center variability in CPAP use suggests that specific indications for this therapy require clarification.

Adolescent↗
PubMed1995

Granulocyte-macrophage colony stimulating factor and Pneumocystis carinii pneumonia in mice.

We hypothesized that therapy with granulocyte-macrophage colony stimulating factor (GM-CSF) would decrease intensity of murine Pneumocystis carinii pneumonia by upregulating alveolar macrophage function. Mice were depleted of CD4+ T lymphocytes and then inoculated intratracheally with P. carinii. Four weeks later, they received recombinant murine GM-CSF (rmGM-CSF) 5 micrograms/d subcutaneously for 7 and 14 d. At the end of therapy lung tissue was scored for intensity of P. carinii infection by silver methenamine stain and for inflammation by hematoxylin-eosin stain. We found that rmGM-CSF therapy significant decreased the intensity scores of PCP infection in comparison to control mice (1.88 +/- 0.47 vs 3.06 +/- 0.12, p < 0.001). Inflammation scores were not significantly different in the rmGM-CSF group compared with the control group (1.83 +/- 0.47 vs 2.83 +/- 0.67). Alveolar macrophages from mice treated with rmGM-CSF released significantly more tumor necrosis factor-alpha (TNF-alpha) than cells from control mice after in vitro stimulation with lipopolysaccharide (LPS) alone (2.65 +/- 0.30 vs 1.45 +/- 0.26 ng/ml, p = 0.01) or with LPS plus murine recombinant interferon-gamma (4.16 +/- 0.51 vs 2.25 +/- 0.34 ng/ml, p = 0.01). We conclude that GM-CSF therapy reduces the intensity of PCP and this effect is associated with an enhanced alveolar macrophage TNF-alpha production.

Animals↗
PubMed1994

Loss of compartmentalization of alveolar tumor necrosis factor after lung injury.

Tumor necrosis factor (TNF), a compartmentalized cytokine, is a key mediator in the systemic inflammatory response syndrome and may play a role in multiorgan failure. To assess whether compartmentalization of alveolar TNF is preserved following lung injury, isolated perfused lungs from Sprague-Dawley rats were given intratracheally 1 ml/kg of phosphate-buffered saline (PBS), 0.1 mg/kg of lipopolysaccharide (LPS), or 125,000 units of murine recombinant TNF (mrTNF). To induce lung leak, one group of rats was given 50 mg/kg of alpha-naphthylthiourea (ANTU) intraperitoneally. Then, 125,000 units mrTNF was given intratracheally to these lungs. Samples of perfusate were assayed for TNF by the L929 cytotoxicity assay before (0 min) and 180 min after the intratracheal challenge, and bronchoalveolar lavage (BAL) was performed for TNF assay. ANTU increased lung leak but intratracheal TNF and LPS did not. The isolated perfused lung preparation expressed small amounts of perfusate TNF and underwent minimal leak that was not caused by TNF release. Endogenous or exogenous intrapulmonary TNF remained predominantly compartmentalized, but following ANTU, TNF readily appeared in the perfusate. Compartmentalization of alveolar TNF is lost during alveolar-capillary injury, suggesting that the injured lung may contribute to a systemic inflammatory response and subsequent multiorgan failure.

Animals↗
PubMed1991

Predicting outcome following pulmonary resection in cystic fibrosis patients.

A small subset of cystic fibrosis (CF) patients develop pulmonary disease primarily limited to one lobe or lung segment requiring prolonged recurrent hospitalizations with intensive medical therapy. Although surgery has been advocated for patients who do not respond to medical therapy, very little is known about criteria for selection of patients who might benefit from resection of the involved parenchyma. In an attempt to further define criteria for pulmonary resection in these patients, we retrospectively reviewed our experience at Tulane Medical Center over the past 10 years. Fourteen patients with CF, ranging from 3 to 30 years of age, underwent 17 pulmonary resections. Indications for surgery were persistent lobar or pulmonary atelectasis and bronchiectasis requiring multiple hospitalizations and unresponsive to medical therapy (n = 13), bronchopleural fistula (n = 2), or hemoptysis not responding to medical therapy or selective embolization (n = 2). Thirteen lobectomies and four pneumonectomies were performed. Only two resections were on the left side and 11 right upper lobectomies were performed. Postoperative hospitalization ranged from 5 to 21 days (mean, 8.5 days). Preoperative pulmonary function tests showed widely divergent function in these patients. Forced expiratory volume (FEV1) ranged from 11% to 88% whereas forced vital capacity (FVC) ranged from 20% to 100% of predicted values. Oxygen saturation ranged from 86% to 99%. Although there was no significant difference in preoperative and postoperative FVC or O2 saturation, there was a significant (P less than .003) decrease in the postoperative FEV1. In the 12 surviving patients followed for at least 1 year, there was also a significant reduction (P less than .001) in the number of hospitalizations required due to pulmonary exacerbations from an average 2.2 admissions per year (range, 0.44 to 3.5 admissions per year) to 1.1 admissions per year (range, 0 to 8).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1990

MR imaging of pancreas in cystic fibrosis.

The pancreatic regions of 18 patients with cystic fibrosis were analyzed with a 1.5 Tesla MR unit. Signal intensity of the pancreas was correlated with clinical data and ultrasound. A hyperintense pancreas on T1-weighted image was consistent with fatty replacement of pancreatic insufficiency. A pancreas of normal soft tissue intensity was found in two asymptomatic and one symptomatic patient. A very hypointense pancreas on any pulse sequence was considered to be an intermediate stage of pancreatic degeneration.

Adolescent↗
PubMed1990

Influence of SK&F 95587 and BN 50730 on bronchoconstrictor responses in the cat.

The effects of SK&F 95587 (4[2-(benzenesulfonamido)-ethyl] phenoxyacetic acid), a thromboxane (TX) receptor blocking agent, on bronchoconstrictor responses were investigated in paralyzed, anesthetized, mechanically ventilated cats. Intravenous injections of the TXA2 receptor mimics, U-46619 [(15S)-hydroxy-11 alpha,9 alpha-(epoxymethano)prosta5Z,13E-dienoic acid] and U-44069 (9,11-dideoxy-11 alpha,9 alpha-epoxymethano PGF2 alpha), produced dose-related increases in transpulmonary pressure and lung resistance and decreases in dynamic compliance. After administration of SK&F 95587, 5 mg/kg i.v., bronchoconstrictor responses to U-46619 and U-44069 were reduced markedly, whereas airway responses to prostaglandin (PG)F2 alpha, serotonin, PGD2 or the PGD2 metabolite, 11 beta-PGF2 alpha, were not altered. The duration of action of SK&F 95587 was greater than 3 hr, and the blockade was overcome when 10-fold larger doses of the TXA2 mimics were administered. Bronchoconstrictor responses to platelet-activating factor (PAF) were blocked by SK&F 95587 and by the novel PAF receptor antagonist, BN 50730. BN 50730 also blocked the fall in systemic arterial pressure in response to PAF. However, BN 50730 did not influence airway responses to U-46619, PGF2 alpha, PGD2 or serotonin and had no effect on baseline bronchomotor tone or arterial pressure. The PAF receptor antagonism with BN 50730 was overcome when 10-fold larger doses of PAF were administered and the dose-response curves for changes in lung resistance and dynamic compliance were shifted to the right in a parallel manner. The present data suggest that SK&F 95587 has selective TX receptor blocking activity, and that BN 50730 has selective PAF receptor blocking properties in the airways of the cat. The present data also provide support for the hypothesis that bronchoconstrictor responses to PAF are mediated by specific receptors, which are coupled to a phospholipase and, when activated, result in the release of TXA2 and contraction of airway smooth muscle.

15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5↗
PubMed1989

Obstructive sleep apnea syndrome in sickle cell disease.

We present a series of 21 children with obstructive sleep apnea syndrome and sickle cell disease (SCD). Thirteen patients underwent adenotonsillectomy with resolution of symptoms and improvement in alveolar hypoventilation. Adenotonsillectomy involves significantly increased risks in patients with SCD. We present our protocol for management of these difficult surgical patients, including vigorous hydration and transfusion therapy. Polysomnography has proven valuable both in diagnosis and in identifying severely affected patients. Increased end tidal alveolar carbon dioxide during sleep has proven to be a significant predictor of disease, while oxygen saturation monitoring was shown to be unreliable. The incidence of adenotonsillar hypertrophy (ATH) in SCD appears increased and not related to infectious diseases. We suggest that ATH represents a part of the natural course of compensatory lymphoid tissue enlargement in children with SCD.

Adenoidectomy↗