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Biomedical subjects

J D Ferguson

Publications and source records attributed to J D Ferguson.

48 records · Page 3Linked to original sources
PubMed1978

Positive end expiratory pressure: effects on lung mechanics of premature lambs.

Pulmonary mechanics were determined at 0, 3, 6, and 10 cm H2O positive and expiratory pressure (PEEP) in premature lambs at a mean gestational age of 134 days. Functional residual capacity increased (p less than 0.005) by 7% (1.6 ml/kg) per cm H2O PEEP. Dynamic lung compliance and specific compliance significantly decreased by 10% (0.11 ml/cm H2O/kg) and 9% (0.0051 l/cm H2O) per cm H2O PEEP, respectively, for PEEP above 3 cm H2O level. Inspiratory lung resistance increased significantly (p less than 0.05) only between 0 and 6 cm H2O PEEP while expiratory lung resistance increased (p less than 0.05) between 0 cm H2O PEEP and all higher levels. The data suggest that PEEP in excess of 3 cm H2O produces undesirable effects on lung mechanics in premature lambs. These results may be important in predicting contraindications and potential complications of positive pressure breathing in the newborn.

Animals↗
PubMed1978

Pulmonary lavage in preterm lambs.

Pulmonary function was studied before and after bilateral lung lavage with oxygenated FC-80 fluorocarbon liquid in seven perterm lambs, 134 days of gestation. Measurements of transpulmoary pressure, airflow, tidal volume, and functional residual capacity (FRC) enabled calculation of lung resistance and compliance, specific compliance, and work of breathing. Immediately postlavage, arterial oxygen tension (PaO2) decreased significantly (P less than 0.05) by 41% from control values. In addition, at 1 hr postlavage, lung compliance significantly decreased (P less than 0.01) by 43% from control levels. Lung resistance, FRC work of breathing arterial carbon dioxide tension, and pH postlavage were not significantly different from prelavage values. The mean volume of FC-80 remaining in the lungs at 1 hr postlavage was 32% of the instilled volume. These data indicate that lung lavage with a low surface tension liquid has a relatively small effect on lung mechanics of the premature lung.

Animals↗
PubMedDate not supplied

Manure sampling for nutrient analysis: variability and sampling efficacy.

Reliable estimation of nutrient concentrations is required to manage animal manure for protecting waters while sustaining crop production. This study was conducted to investigate sample variability and reliable nutrient analysis for several manure types and handling systems. Serial samples were collected from dairy, swine, and broiler poultry operations while manure was being loaded onto hauler tanks or spreaders for field application. Samples were analyzed for total solids (TS), total nitrogen (N), ammoniacal nitrogen (NH4-N), total phosphorus (P), and potassium (K). The least number of samples needed for reliable testing of total N and P, defined as +/- 10% of the experimental means with 99% probability, was obtained for each farm using a computer-intensive random resampling technique. Sample variability within farms, expressed as the coefficient of variation (CV), was mostly 6 to 8% for farms that used agitation of manure storages but several times higher (20-30%) on farms where no agitation was applied during the sampling period. Results from the random resampling procedure indicated that for farms that used agitation, three to five samples were adequate for a representative composite for reliable testing of total N and P; whereas for farms without agitation, at least 40 samples would be required. Data also suggest that using book values for manure nutrient estimations could be problematic because the discrepancies between book standards and measured farm data varied widely from a small amount to several fold.

Agriculture↗
PubMedDate not supplied

Efficacy of alum and coal combustion by-products in stabilizing manure phosphorus.

Animal manures contain large amounts of soluble phosphorus (P), which is prone to runoff losses when manure is surface-applied. Here we report the efficacy of alum and three coal combustion by-products in reducing P solubility when added to dairy, swine, or broiler litter manures in a laboratory incubation study. Compared with unamended controls, alum effectively reduced readily soluble P, determined in water extracts of moist manure samples with 1 h of shaking, for all three manures. The reduction ranged from 80 to 99% at treatment rates of 100 to 250 g alum kg(-1) manure dry matter. The fluidized bed combustion fly ash (FBC) reduced readily soluble P by 50 to 60% at a rate of 400 g kg(-1) for all three manures. Flue gas desulfurization by-product (FGD) reduced readily soluble P by nearly 80% when added to swine manure and broiler litter at 150 and 250 g kg(-1). Another by-product, anthracite refuse fly ash (ANT), was ineffective for all three manures. In all cases, reduction in readily soluble P is primarily associated with inorganic phosphorus (P(i)) with little change in organic phosphorus (P(o)). Sequential extraction results indicate that the by-product treatments shifted manure P from H2O-P into a less vulnerable fraction, NaHCO3 - P, while the alum treatment shifted the P into even more stable forms, mostly NaOH-P. Such shifts in P fractions would have little influence on P availability for crops over the long-term but would retard and reduce potential losses of P following manure applications.

Agriculture↗
PubMedDate not supplied

Bisoprolol alone and in combination with amlodipine or nifedipine in the treatment of chronic stable angina.

Beta-blockers and calcium antagonists are both effective monotherapy for stable angina. When symptoms persist, these two agents are commonly co-prescribed in the hope that this combination has added benefit compared with monotherapy alone. We investigated the additional efficacy of the calcium antagonists amlodipine and nifedipine when added to bisoprolol in patients with stable angina. Patients were randomised in a multicentre, single-blind study, with crossover of three treatments consisting of bisoprolol 10 mg once daily, bisoprolol plus nifedipine 20 mg twice daily, and bisoprolol plus amlodipine 5 mg once daily. Exercise tests were performed at the end of each four-week study period and the exercise time to onset of angina was assessed. A total of 198 patients from 17 centres were recruited of whom 147 were evaluable for efficacy. There were no statistically significant differences in exercise duration to onset of angina between any of the groups. The combination of bisoprolol plus nifedipine was least well tolerated. In summary, this study suggests there is little benefit in adding a calcium antagonist to bisoprolol in treating patients with stable angina.

Adolescent↗