Search PubMed⌕ Search

Biomedical subjects

A Bush

Publications and source records attributed to A Bush.

At least 127 records · Page 7Linked to original sources
PubMed1999

Cardiorespiratory responses to negative pressure ventilation after tetralogy of fallot repair: a hemodynamic tool for patients with a low-output state.

OBJECTIVES: We hypothesized that a period of cuirass negative pressure ventilation (NPV) would augment the cardiac output of patients in the early postoperative period after complete correction of tetralogy of Fallot (TOF). BACKGROUND: Diastolic right ventricular dysfunction can lead to a low-output state in an important minority of patients after TOF repair. In these patients, the diastolic pulmonary arterial flow, which characterizes restrictive right ventricular physiology, and on which the cardiac output is so dependent, is highly sensitive to changes in intrathoracic pressure. METHODS: The effects of NPV on pulmonary blood flow were investigated in 23 intubated children who were initially ventilated using intermittent positive pressure ventilation after TOF repair. Eight patients had restrictive right ventricular physiology. All children received a 15-min period of NPV, and eight received a prolonged period (45 min) of NPV. RESULTS: A brief period of NPV increased pulmonary blood flow by 39%, and the improvement further continued if the study period was extended, with a total increase of 67% after 45 min. Patients with restrictive physiology had a somewhat delayed response to NPV, but the ultimate increase during an extended period of NPV was greater in restrictive patients (84%) than nonrestrictive patients (50%). CONCLUSIONS: By manipulating important cardiopulmonary interactions, NPV improves the cardiac output of patients after TOF repair, and has a role as a hemodynamic tool in the management of the low-output state in selected cases.

Blood Flow Velocity↗
PubMed1999

Left bronchial isomerism, normal atrial arrangement and bronchomalacia mimicking asthma: a new syndrome?

Three children who presented with steroid-resistant airflow obstruction are described. They all had bronchomalacia in the setting of a rare visceral arrangement, namely left bronchial isomerism with normal atrial arrangement. Imaging and, in two cases, a normal residual volume in the face of severe airflow obstruction were diagnostic pointers to a nonasthmatic cause of wheeze. Although the association of these abnormalities may be coincidental, together they may constitute a new clinical syndrome.

Abnormalities, Multiple↗
PubMed1999

Open lung biopsy for diffuse interstitial lung disease in children.

The aim of the study was to investigate the contribution that open lung biopsy makes to the management of children with diffuse interstitial lung disease and to review the procedure-related morbidity in comparison with published literature on other biopsy techniques. The authors reviewed the case notes and histology of patients under 18 yrs who had had an open lung biopsy in 1991-1998 for investigation of diffuse interstitial lung disease. The majority of patients returned from theatre breathing spontaneously and without an intercostal drain. Three out of 27 suffered a complication related to the biopsy that required intervention. A clear histological diagnosis was reached in 25/27 patients resulting in a change of management in 15/27. The most common histological patterns were nonspecific interstitial pneumonitis which generally had a favourable prognosis and follicular bronchiolitis/lymphocytic interstitial pneumonitis where prognosis was largely dependent on that of an underlying systemic disorder. It is concluded that open lung biopsy makes a substantial contribution to the management of diffuse interstitial lung disease in children and considering both diagnostic yield and safety, remains the biopsy technique of choice.

Adolescent↗
PubMed1999

Reduction in the adherence of Pseudomonas aeruginosa to native cystic fibrosis epithelium with anti-asialoGM1 antibody and neuraminidase inhibition.

The high incidence of colonization of the cystic fibrosis (CF) airway with Pseudomonas aeruginosa has been attributed to several mechanisms including increased numbers of asialoglycolipid receptors, which may be further increased by exposure to the bacterial exoproduct, neuraminidase. This study examined whether the adherence of P. aeruginosa to fresh CF respiratory epithelial cells can be reduced in vitro by anti-asialoGM1 (anti-aGM1) antibody, neuraminidase inhibition, or the use of asialoGM1 tetrasaccharide as a competitive inhibitor. CF nasal epithelial cells were incubated with a nonmucoid strain of P. aeruginosa, in the presence or absence of a polyclonal anti-aGM1 antibody, the neuraminidase inhibitor 2,3-dehydro-2-deoxy-N-acetyl-neuraminic acid (DANA), or the tetrasaccharide moiety of aGM1. Adherence of bacteria to the apical surface of ciliated epithelial cells was quantified using scanning electron microscopy. Incubation of the cells with bacteria in the presence of either anti-aGM1 antibody or DANA significantly reduced bacterial adherence by 51(7)%, (p<0.01), and 34(9)%, (p<0.01), respectively. In contrast, no significant effect on P. aeruginosa binding was seen in the presence of aGM1 tetrasaccharide. The data are consistent with previous studies on cultured cells, and suggest that the in vivo effects of such interventions should be explored as potential mechanisms to reduce Pseudomonas aeruginosa colonization in cystic fibrosis.

Adult↗
PubMed1999

The effects of surgically treated pulmonary stenosis on lung growth and cardiopulmonary function in children during rest and exercise.

The effects of high pulmonary blood flow and pressure on pulmonary development are well understood, but the effect of low pulmonary flow/pressure is not. Pulmonary stenosis (PS) was therefore used as a model to determine its effect on lung development, which was assessed noninvasively by carbon monoxide transfer at rest and during exercise. One hundred and six control children (55 males, 8-16 yrs) and 11 children with isolated valvar or subvalvar PS surgically corrected > or =10 yrs prior to the study without residual stenosis/regurgitation were evaluated. Measurements of effective pulmonary blood flow, stroke volume, arteriovenous oxygen difference (AVO), transfer factor and transfer constant, alveolar ventilation and anaerobic threshold were performed using a mass spectrometer. Data from the normal children allowed calculation of z-scores for the study group matched for age, sex, pubertal stage and surface area. PS children at rest had a significantly lower forced expired volume in one second, cardiac frequency and transfer constant with a raised oxygen consumption and AVO which persisted on exercise. During exercise, the cardiac frequency was 12 beats x min(-1) slower and AVO 0.017 L greater than controls (p<0.05). A persistently mildly raised effective functional residual capacity (0.2 L x m(-2)) during exercise led to a reduced transfer constant (0.35 mmol x min(-1) x kPa(-1) x L(-1)), although the percentage rise (28%) from rest to peak exercise was normal. The percentage fall in stroke volume from the penultimate exercise stage to peak exercise stage was greater in PS children (24%, 95% confidence interval 11-37) than control children (2.4, -2-10, p<0.005). In conclusion, although the effects are small, pulmonary stenosis does affect cardiopulmonary function after surgery. This needs to be considered when contemplating the timing of treatment.

Adolescent↗
PubMed1999

Nasal and lower airway level of nitric oxide in children with primary ciliary dyskinesia.

Exhaled nitric oxide can be detected in exhaled air and is readily measured by chemiluminescence. It is thought to be involved in both the regulation of ciliary motility and host defence. Recently, upper airway NO has been found to be reduced in a small number of children with primary ciliary dyskinesia (PCD) and its measurement has been recommended as a diagnostic test for this condition. The aim of this study was to compare the levels of NO in the upper and lower airways in a larger number of children with proven PCD with those found in healthy children. Exhaled NO was measured in the upper airway by direct nasal sampling during a breath-hold and in the lower airway as the end-tidal plateau level, using a chemiluminescence NO analyser. Upper airway NO levels were significantly lower in PCD (n = 21) than in the healthy children (n = 60) (mean +/-SD, 97+/-193, 664+/-298 parts per billion (ppb), respectively, p<0.0001). In PCD, the lower airway NO levels were also reduced (2.17+/-1.18, 5.94+/-3.49 ppb, respectively, p<0.0001). The levels were not associated with steroid use and did not correlate with lung function. Although there was some overlap between normal children and those with primary ciliary dyskinesia with regard to lower airway NO, nasal NO discriminated between the two groups in all but one child in each group. Measurement of nasal NO therefore may be a useful screening test for primary ciliary dyskinesia.

Breath Tests↗
PubMed1998

c-myc null cells misregulate cad and gadd45 but not other proposed c-Myc targets.

We report here that the expression of virtually all proposed c-Myc target genes is unchanged in cells containing a homozygous null deletion of c-myc. Two noteworthy exceptions are the gene cad, which has reduced log phase expression and serum induction in c-myc null cells, and the growth arrest gene gadd45, which is derepressed by c-myc knockout. Thus, cad and gadd45 are the only proposed targets of c-Myc that may contribute to the dramatic slow growth phenotype of c-myc null cells. Our results demonstrate that a loss-of-function approach is critical for the evaluation of potential c-Myc target genes.

Animals↗
PubMed1998

The value of ultrafast computed tomography in the investigation of pediatric chest disease.

Ultrafast computed tomography (CT) can be performed in almost all children with little or no sedation. The benefit has to be balanced against financial cost and radiation dose. Since observing a steady increase in numbers of scans performed, we analyzed the contribution to management of 106 pediatric chest CT scans performed over a 12-month period. Forty-eight of 106 yielded a positive diagnosis and a further 43/106 provided clearly useful information. CT was most useful in children with chronic productive cough (21/48 scans showed bronchiectasis) and suspected interstitial lung disease. It was least useful in the preoperative assessment of empyema complicating community-acquired pneumonia (0/11 scans giving information that changed management). We conclude that the increased ease of performance of chest CT in children has not led to a large number of inappropriate requests. In the large majority of cases, diagnostically useful information was provided.

Adolescent↗
PubMed1998

The association of cigarette smoking and alcohol consumption with other cardiovascular risk factors in men from Seoul, Korea.

PURPOSE: To explore the effects of cigarette smoking and alcohol consumption on cardiovascular disease risk factors such as hypertension, dyslipidemia, and glucose intolerance in Korean men. METHODS: In this cross-sectional study, we gathered the smoking and drinking history by self-administered questionnaire between June 1994 and May 1995 among 1053 men, age 20-77, who visited a prevention center for a multiphasic health check at St. Mary's Hospital, Seoul. RESULTS: Cigarette smoking had a significant inverse association with systolic and diastolic blood pressure. Adjusted for age, body mass index (BMI), and alcohol consumption, the odds ratio of hypercho-lesterolemia (> or = 240 mg/dl) was 1.30 (95% confidence interval (CI) 1.09-1.55), lower high density lipoprotein (HDL) cholesterol (< 40 mg/dl) was 1.29 (95% CI 1.08-1.54), higher low density lipoprotein (LDL) cholesterol (> or = 160 mg/dl) was 1.30 (95% CI 1.07-1.56), and hypertriglyceridemia (> or = 200 mg/dl) was 1.40 (95% CI 1.16-1.68) among men who smoked 21-30 cigarettes per day compared with nonsmokers. Adjusted for age. BMI, and cigarette smoking in men who consumed 90-179 and 180-269 g/week of alcohol compared with nondrinkers, the odds ratio of hypertension was 1.73 (95% CI 1.01-3.00) and 1.48 (95% CI 1.01-2.17), respectively. Alcohol consumption had a significant protective effect (adjusted odds ratio: 0.60-0.78) against lower HDL cholesterol in all categories > or = 90 g of alcohol per week compared with nondrinkers. The adjusted odds ratio of hypertriglyceridemia was 1.17 (95% CI 1.04-1.31), and glucose intolerance (fasting blood sugar (FBS) > or = 120 mg/dl) was 1.27 (95% CI 1.11-1.14) among those who consumed > or = 360 g/week of alcohol compared with nondrinkers. CONCLUSIONS: In this Korean population study, although alcohol consumption increased HDL cholesterol, which might have a protective effect on coronary heart disease, cigarette smoking was associated with decreased blood pressure, smoking was confirmed to have dyslipidemic effect such as increasing total cholesterol, LDL cholesterol, triglyceride and decreasing HDL cholesterol, and alcohol consumption was confirmed to be associated with hypertension, hypertriglyceridemia, and glucose intolerance as in Caucasian. Further prospective intervention studies are needed for evaluating cardiovascular effects after cessation of smoking and drinking.

Adult↗
PubMed1998

Beta-amyloid augments platelet aggregation: reduced activity of familial angiopathy-associated mutants.

The beta-amyloid (A beta) peptide is present both in serum and in platelets, however it is unclear whether A beta plays a role in platelet function. We have now investigated the effects of soluble A beta on platelet function and have found that low levels (0.1-1 nM) of soluble A beta augment ADP-dependent platelet aggregation and translocation of focal adhesion kinase to the platelet cytoskeleton. Addition of A beta to gel-filtered platelets along with concentrations of adenosine diphosphate (ADP) producing submaximal aggregation responses increased the aggregation response by over 2-fold depending on the ADP:A beta ratios. The structure activity requirements for A beta activity showed intriguing constraints. Only full length A beta has significant activity. Truncated A beta peptides, such as A beta(1-16) or A beta(25-35), or reverse A beta(40-1) all show little or no activity. We also examined the activity of mutant A beta peptides, corresponding with the APP(692A-G) and APP(693E-Q) (at A beta21 and A beta22, respectively) which are found in familial Alzheimer's disease and hereditary cerebral hemorrhagic amyloidosis, Dutch type (HCHWA-D), and found that these peptides showed little or no activity. These results suggest that A beta interacts with platelets in a highly specific manner and may play a role in regulating platelet function.

Adenosine Diphosphate↗
PubMed1998

Pulmonary response of normal human subjects to inhaled vasodilator substances.

1. Inhaled vasodilators such as nitric oxide and epoprostenol (prostaglandin I2) are now widely employed as supportive therapies to improve oxygenation and reduce pulmonary vascular resistance in patients with acute and chronic pulmonary hypertension. However, few data exist concerning their effects in normal individuals. The aim of this study was to characterize the response of the pulmonary circulation in normal individuals to inhaled nitric oxide and nebulized prostaglandin I2.2.Eight healthy volunteers were exposed to inhaled nitric oxide (0, 20 and 40 p.p.m.) and nebulized prostaglandin I2 (10 microgram/ml). Changes in effective pulmonary blood flow and diffusing capacity of the lung for carbon monoxide (TLCO) were measured using respiratory mass spectrometry. Bicycle ergometry was used to increase effective pulmonary blood flow as a positive control.3. Exercise produced significant increases in both effective pulmonary blood flow and TLCO, but neither nitric oxide nor prostaglandin I2 produced significant changes in either parameter.4.No significant change in pulmonary haemodynamics was demonstrated in response to inhaled nitric oxide or nebulized prostaglandin I2, using doses known to be effective in patients with acute and chronic pulmonary hypertension. These data suggest that the normal pulmonary vascular bed is not amenable to vasodilatation by inhaled drugs. The study further suggests that the normal pulmonary vasodilatation seen on exercise is not mediated pharmacologically, but is a secondary consequence to the mechanical effects of a rise in pulmonary blood flow. This study thus supports the view that there is no resting vasoconstrictor tone in the pulmonary vascular bed.

Administration, Inhalation↗
PubMed1998

The value of classifying interstitial pneumonitis in childhood according to defined histological patterns.

AIMS: Interstitial pneumonitis in children is very rare and most cases have been classified according to their counterparts in adults, although the term 'chronic pneumonitis of infancy' has recently been proposed for a particular pattern of interstitial lung disease in infants. We reviewed our paediatric cases of interstitial pneumonitis, first, to look at the spectrum of histological patterns found in this age group and, second, to determine whether the classification of such cases in childhood is both appropriate and worthwhile. METHODS AND RESULTS: Twenty-five of 38 open lung biopsies showed an overlapping spectrum of interstitial pneumonitis, including three cases that fulfilled the histological criteria for chronic pneumonitis of infancy. There were 11 cases of reactive pulmonary lymphoid hyperplasia (either lymphoid interstitial pneumonitis or follicular bronchiolitis), five of which were associated with abnormalities of the immune system. Four cases were classified as desquamative interstitial pneumonitis and the remaining seven cases were classified as nonspecific interstitial pneumonitis. There were no cases with the histological features of usual interstitial pneumonitis. Most patients responded to steroids but tended to have a residual deficit in lung function. Mortality appeared to be associated with presentation at a young age. CONCLUSION: Classification of interstitial pneumonitis according to their adult counterparts is appropriate for this younger age group and can provide valuable information for the clinician. The term 'chronic pneumonitis of infancy' refers to a specific histological pattern, but whether it represents a separate disease or a reflection of pulmonary immaturity remains to be proven.

Adolescent↗