Novel Göttingen Miniswine Model of Heart Failure With Preserved Ejection Fraction Integrating Multiple Comorbidities

A lack of preclinical large animal models of heart failure with preserved ejection fraction (HFpEF) that recapitulate this comorbid-laden syndrome has led to the inability to tease out mechanistic insights and to test novel therapeutic strategies. This study developed a large animal model that integrated multiple comorbid determinants of HFpEF in a miniswine breed that exhibited sensitivity to obesity, metabolic syndrome, and vascular disease with overt clinical signs of heart failure. The combination of a Western diet and 11-deoxycorticosterone acetate salt-induced hypertension in the Göttingen miniswine led to the development of a novel large animal model of HFpEF that exhibited multiorgan involvement and a full spectrum of comorbidities associated with human HFpEF.

Assessing quality of life in Mexican-American children with asthma: impact-on-family and functional status

OBJECTIVE

To assess the internal consistency reliability and construct validity of two questionnaires, the Impact on Family (IOF) and the Functional Status II (R) (FSIIR), in a Mexican-American population of children with asthma.

METHODS

We interviewed 115 Hispanic parents of children with asthma and compared the IOF and FSIIR scores and reliability coefficients for the following subgroups: English or Spanish language and high or low educational level. We assessed the construct validity of the IOF Total score and FSIIR Illness score by examining the relationship between these scores and other health status variables.

RESULTS

The IOF Total score and FSIIR Illness score demonstrated acceptable construct validity and reliability for language and education subgroups, although several of the IOF subscales had low reliability.

CONCLUSIONS

IOF Total score and FSIIR Illness score can be recommended for use by Spanish- and English-speaking Mexican-American respondents.

Implementation of individualized patient education for Hispanic children with asthma

An educational program known as the Childhood Asthma Project (CAP) was implemented to reduce morbidity among Hispanic children with chronic asthma. Seventy-three children, ages 6-16, participated in 4 program phases: baseline assessment, one-on-one child-centered education, application, and maintenance. During baseline assessment, child and parent asthma beliefs and behaviors were evaluated and used to create educational modules on symptom recognition, peak low meters, medications, and precipitating factors in Spanish and English. Children learned the importance of self-management, practiced using inhalers and peak flow meters and charted peak flow recordings. Videotapes provided peer modeling by showing Hispanic children with asthma performing self-management tasks. During the application phase, patients practiced self-management behaviors at home and reviewed progress with a nurse educator. During maintenance, the success of self-monitoring was reviewed at follow-up appointments. Recommendations for designing health education interventions for Hispanic children are provided.

Dental management of children with asthma

Asthma affects about 1 in 10 children. The condition is characterized by acute respiratory distress brought on by environmental factors. The condition is treated with medications aimed to reduce reaction to stimulants by the airway. Dental management involves attention to the status of the patient and awareness of stimulants of the reactive airway. Clinical recommendations are provided.

Implementation of a physician education intervention. The Childhood Asthma Project

OBJECTIVES

To increase pediatric residents' knowledge of the Guidelines for the Diagnosis and Management of Asthma (GDMA) developed by the Expert Panel of the National Asthma Education Program and to increase the residents' confidence in their ability to implement these guidelines. Emphasis was placed on the diagnosis and treatment of Hispanic children with asthma, a population at increased risk for morbidity.

SETTING

A continuity care clinic located in an urban ambulatory care facility.

SUBJECTS

Forty-four pediatric residents: 17 first-year residents, 15 second-year residents, and 12 third-year residents.

METHODS

Residents participated in a multicomponent asthma management curriculum that stressed active learning strategies, including the following: focus groups, computer-based testing, lectures, hands-on skill development seminars, role modeling by attending pediatricians, provision of GDMA pocket cards and posters, access to peak flowmeters and spirometry, and an interactive computer-based module. Content focused on pulmonary function testing with spirometry and peak flowmeters, stepwise use of medications, recognition of asthma symptoms and triggers, and cultural considerations that impact asthma management. Pediatric faculty and fellows also participated in a series of asthma seminars to increase the likelihood that faculty would role model the GDMA and provide appropriate feedback to residents.

RESULTS

Pediatric residents demonstrated significant increases in knowledge about evaluation of asthma, pulmonary function testing, and clinical management, displayed significantly enhanced levels of confidence, and were enthusiastic about the asthma management curriculum, rating it significantly higher than 15 other content areas in the general pediatric curriculum.

Vancomycin and tobramycin clearance in an infant during continuous hemofiltration

OBJECTIVE

To report a case of vancomycin and tobramycin clearance by continuous veno-venous hemofiltration in an infant. Hemofiltration clearance (ClHF) was calculated by two methods and compared for ease and reliability.

METHODOLOGY

Case report of a hospitalized four-month-old infant. With method A, ClHF calculation for vancomycin and tobramycin was determined by accurate collection of ultrafiltrate in five 24-hour periods and a midpoint serum sample. With method B, ClHF calculation was determined by obtaining prefilter sample, postfilter sample, and blood flow through filter (Fick principle) over three study periods, correlating to three of five study periods in method A.

RESULTS

The infant received continuous veno-venous hemofiltration. With method A, vancomycin ClHF ranged from 0.27 to 0.80 mL/min; tobramycin ClHF ranged from 0.32 to 0.91 mL/min. With method B, ClHF for vancomycin ranged from 0 to 2.08 mL/min. Tobramycin ClHF ranged from 0 to 1.6 mL/min when calculated with method B.

CONCLUSIONS

Continuous veno-venous hemofiltration increased the clearance of vancomycin and tobramycin requiring dosage modifications. It appears that method A, which uses the ultrafiltration concentration compared with the serum concentration is more accurate than method B, as it averages fluctuations in ultrafiltrate flow rates. Method B compares a single pre- to postfilter drug concentration and relies on an accurate measurement of ultrafiltration flow rate. Determining ClHF based upon one point in time may overestimate ClHF when the ultrafiltration flow rate varies, as it does in the critically ill. Daily serum concentrations for vancomycin and tobramycin are recommended during continuous veno-venous hemofiltration.

Hispanic children with asthma: morbidity

Hispanic children represent a large and growing segment of the poor and disadvantaged children in our country. Asthma and other chronic respiratory diseases have a significant impact on poor children. Yet there are few descriptions of the specific morbidities and barriers to health that Hispanic children with asthma encounter, and data on predictors of morbidity among these children are unavailable. The purpose of this study is to describe the morbidity associated with asthma in Hispanic children and to identify factors that predict morbidity. A group of Hispanic children with moderate asthma followed in the clinics of the University of Texas Health Science Center at San Antonio were studied. Children aged 6 to 16 years with at least two acute-care visits or one hospitalization for asthma during the previous year were enrolled. Data sources included standardized questionnaires, spirometry, medical records, and school attendance records. Seventy-eight Hispanic children were enrolled in the study (mean age = 9.4 +/- 2.7 [SD]; 62% male). Fifty-two (67%) of children had been hospitalized previously. The other morbidity variables (mean +/- SD) were number of days/week impaired (1.1 +/- 1.2), number of days absent from school per year (13 +/- 9.6), number of acute-care visits per year (3.3 +/- 2.4), and number of hospital admissions per year (0.6 +/- 0.8). The mean forced expiratory volume in 1 second/forced vital capacity was 79.3% (+/- 9.1) and the mean forced expiratory flow, mid-expiratory phase, percent predicted was 69.9% (+/- 25.1). Thirty-four children (44%) were exposed to cigarette smoke in the home.(ABSTRACT TRUNCATED AT 250 WORDS)

The effects of cyclosporine and dexamethasone on an alveolar macrophage cell line (NR8383)

Lung infections are a major source of morbidity and mortality in recipients of lung transplants. Prominent among the pathogens that cause pneumonias in these subjects are gram-negative bacilli, particularly Pseudomonas strains. One important reason that bacteria infect the lungs of these patients is that pulmonary defenses are impaired by the drugs used to prevent transplant rejection. Using a rat alveolar macrophage cell line (NR8383), we measured the effects of exposure (24 hr) to cyclosporine and dexamethasone (DEX) on the ability of these cells to (1) kill Pseudomonas aeruginosa (Pa); (2) produce H2O2; and (3) release tumor necrosis factor. We found that the bactericidal activity against unopsonized or opsonized Pa of NR8383 cells was unaltered by CsA (0.1, 0.5, or 1 micrograms/ml), DEX (10(-6) M), or CsA + DEX (0.5 micrograms/ml + 10(-6) M, respectively). Likewise, LPS-induced TNF release, and zymosan A and Pa-induced H2O2 production were unaltered by CsA (0.1 or 1 microgram/ml). In contrast, H2O2 production and TNF release were decreased by about 50% and 90%, respectively, by DEX exposure (10(-6) M). Thus, while DEX but not CsA decreased TNF release and H2O2 production in NR8383 cells, bactericidal activity against Pa was unaffected. One explanation for these results is that decreases in TNF or H2O2 of the magnitude we observed do not impair bactericidal activity against Pa; however, an alternative explanation is that Pa are killed by NR8383 cells through other mechanisms. Interpretation of these results must take into consideration the fact that macrophages from different species and tissues may respond differently to various stimuli.

Pneumocystis carinii induces an oxidative burst in alveolar macrophages

There is evidence that alveolar macrophages (AM) play a role in the clearing of Pneumocystis carinii from the lungs. To investigate the mechanisms involved in this process, we studied in vitro the induction of an oxidative burst by P. carinii in a cell line of macrophages (NR8383) and AM from normal rats. P. carinii was added to macrophage monolayers (10(6) cells), and the H2O2 produced after 4 h of incubation was measured. Both NR8383 macrophages and normal rat AM produced H2O2 in response to P. carinii cysts and trophozoites isolated from dexamethasone-treated rats, although the amount of H2O2 induced in AM from normal rats was larger. NR8383 macrophages bound and phagocytized both P. carinii cysts and trophozoites and produced increasing amounts of H2O2 as a dose-related response to cysts and trophozoites. Opsonization of P. carinii with normal rat serum increased H2O2 production by both types of macrophages; this enhancement was decreased, but not abolished, when the serum was first depleted of complement by heat treatment. These findings demonstrate that NR8383 macrophages and normal rat AM produce an oxidative burst in response to P. carinii and that this response is enhanced by complement.

Role of the zymolyase-sensitive cyst wall of Pneumocystis carinii in the oxidative burst of macrophages

Alveolar macrophages are thought to participate in clearing Pneumocystis carinii (Pc) from the lungs. We have recently demonstrated that Pc cysts and trophozoites induce an oxidative burst in a cell line of rat alveolar macrophages (NR8383). In order to investigate the mechanism of this response, we examined the effect that disruption of the Pc cyst wall with zymolyase had on the cyst's ability to elicit H2O2 from NR8383 macrophages and correlated these results with the electron microscopic appearance of the cyst wall.

Frequency spectra of normal breath sounds in childhood

Clinicians who auscultate the chest of normal children note that the frequency content of their breath sounds appears to vary with age. Because these changes have not been systematically documented before, we recorded and analyzed inspiratory breath sounds in 35 children (0 to 13 years) and five adults (34 to 43 years). Our objective was to determine if the frequency content of normal breath sounds differed with age. Using a Fast Fourier Transform program, we calculated an average amplitude frequency spectrum from the inspiratory portion of the breath sounds of each subject (n = 10 breaths), and we compared the shape of the AFS and the values of selected frequency parameters. We found that the shape of the AFS of the youngest children differed most from the AFS of adults. Three of four selected frequency parameters (F25, F50, F95) differed significantly between children and adults (p less than 0.05), and one parameter (F75) did not (p = 0.11). The F25, F50, and F75 parameters of children (but not F95) were correlated (p less than 0.001) with increasing height and age. These results suggest that differences in the frequency content of the normal breath sounds of children and adults contribute to the differences that clinicians detect during clinical auscultation.

Heavy metal composition of polysomal fractions following cadmium challenge

Endogeneous levels of zinc and copper were found to be 1.2±0.1×10(-2) and 0.3±0.1×10(-2) μg/A260 unit, respectively, in polysomal fractions from control animals; cadmium, however, was undetectable. In experimental animals (injected with cadmium) zinc, copper, and cadmium were found in polysomal fractions isolated by two different methods. One hour after a cadmium injection there was a rise in both the zinc and copper content of the polysomal fractions, which then declined steadily to below control levels by 16 h. Neither zinc nor cadmium were dialyzable from these fractions by a TRIS buffer; however, addition of 0.01M EDTA to the buffer resulted in removal of 75% of the zinc and all of the detectable cadmium.The addition of cadmium (CdCl2) to control supernatants (adjusted to the cadmium concentration present in supernatants 6 h after in vivo exposure) resulted in metal binding to polysomal fractions in levels comparable to those observed after in vivo exposures to the metal. When cadmium was added in the form of cadmium thionein, a smaller fraction of the metal was isolated with the polysomal fraction. Cadmium bound to polysomal fractions in vivo (24 h after exposure) was sensitive to release by protease digestion, but insensitive to release by ribonuclease digestion.

Induction of cadmium-thionein in isolated rat liver cells

The uptake of cadmium by isolated liver cells was linearly related to the cadmium concentration to which the cells were exposed in the medium. Cadmium-treated cells synthesized proteins de novo with the characteristics of cadmium-thionein induced in the liver of cadmium-treated animals. Thionein from liver cells incorporated cadmium and [35S]cysteine, had a Ve/Vo (Sephadex G-50) of 1.8-1.9, and was separated into two subfractions by DEAE-cellulose ion-exchange chromatography. Cycloheximide and actinomycin D when added after a cadmium exposure prevented the synthesis of thionein. However, addition of actinomycin D after synthesis had started only decreased the total amount of thionein synthesized. The concentration of cadmium to which the cells were exposed affected the amount of cadmium-thionein synthesized in 6h. The maximum response occurred when cells were exposed to 0.5 microgram of cadmium/ml; at higher metal concentrations the total amount of cadmium-thionein synthesized declined. The system described in the present paper can be used to study the mode of metal toxicity and the mechanism of cadmium-thionein synthesis.