Effect of positioning on recorded lung sound intensities in subjects without pulmonary dysfunction.

BACKGROUND AND PURPOSE: Physical therapists often use positioning to assist in the reexpansion of collapsed lung segments. An increase in lung sound intensity on auscultation is considered indicative of lung expansion. This study was designed to examine whether clinical interpretation of auscultatory findings is warranted. SUBJECTS: The subjects (5 male, 6 female) were young physical therapist students without pulmonary dysfunction (mean age=20.4 years, mean height=166.3 cm, mean weight=57.5 kg). Subjects with lung disease were excluded because pulmonary pathology is difficult to standardize. METHODS: Lung sounds electronically recorded over the posterior chest wall of subjects in sitting and side-lying positions were compared. Measures included peak intensity, frequency at maximum power, and median frequency. RESULTS: In the sitting position, inspiratory sounds recorded over the left posterior chest wall were louder than those recorded on the right side. In the side-lying positions, the sound intensity recorded from the dependent chest wall was louder than that recorded from the nondependent chest wall. In side-lying positions, the upper hemithorax is "nondependent," and the side in contact with the bed is "dependent." Sound intensities recorded over both posterior chest walls in the sitting position were louder than those recorded over the same lung area in the nondependent side-lying position. There was no difference in the sound intensity recorded between the sitting and dependent side-lying postures. CONCLUSION AND DISCUSSION: When comparative auscultation of the chest wall is used by physical therapists to assess the adequacy of pulmonary ventilation, patient posture and regional differences in breath sound intensity can influence clinical interpretation.     

Ranitidine kinetics in normal subjects

A 1-mg/kg IV bolus injection and a 150-mg (one tablet) oral dose of ranitidine were given to seven normal subjects. At least 1 wk separated the two doses. Ranitidine disappeared from plasma with a half-life of about 2.5 hr. Half of the oral dose was effectively absorbed and half of the absorbed amount was found unchanged in urine. Total body clearance was 10.1 ml/min/kg. Urinary clearance was the same after oral and intravenous doses (6.4 and 6.9 ml/min/kg, P greater than 0.10). Intravenous ranitidine kinetics included three phases, with a central distribution volume of 0.2 l/kg and a total distribution volume of 1.2 l/kg. Absorption kinetics were apparently order zero: of the 150-mg dose, 75 mg was absorbed during 5 hr at a constant rate of 15 mg/hr.     

Immune complexes in normal subjects

Immune complex (IC) levels were measured in normal subjects using the C1q solid phase, C1q deviation, C1q binding and polyethylene glycol precipitation assays. Significant changes in IC levels were seen in normals with each of the assays but the pattern of variation was not consistent between assays or subjects or in the same subject from day-to-day. There were no consistent changes with meals, time of day, exercise or the prior administration of prednisone. Low levels of IC appear to be normal in plasma but the variation in IC levels is not explained. Normal IC may well comprise mixtures of non-specific immunoglobulin aggregates, rheumatoid factor-immunoglobulin complexes, idiotype-anti-idiotype complexes as well as specific antibody complexes with antigens from food, infective agents and other sources.     

Neutrophil depletion attenuates interleukin-8 production in mild-overstretch ventilated normal rabbit lung

OBJECTIVE: Acute lung injury induced by lung overstretch is associated with neutrophil influx, but the pathogenic role of neutrophils in overstretch-induced lung injury remains unclear. DESIGN: To assess the contribution of neutrophils, we compared the effects of noninjurious large tidal volume (Vt) ventilation on lungs in normal and neutrophil-depleted animals. SETTING: Research animal laboratory. SUBJECTS: Twenty-six male Japanese white rabbits. INTERVENTIONS: Animals were mechanically ventilated for 4 hrs with one of the three following protocols: large Vt (20 mL/kg), small Vt (8 mL/kg), and large Vt (20 mL/kg) with neutrophil depletion achieved by a single dose of vinblastine injection (0.75 mg/kg) intravenously 4 days before the experiment. MEASUREMENTS AND MAIN RESULTS: Large Vt ventilation produced alveolar neutrophil influx compared with low Vt (p =.002) without evidence of edema or increased epithelial permeability. The neutrophil influx was accompanied by increases in interleukin-8 in bronchoalveolar lavage fluid (p =.04). Immunohistochemistry of large Vt lungs showed increased interleukin-8 staining in bronchial epithelial cells, alveolar epithelium, alveolar macrophages, and smooth muscles of pulmonary vessels. Neutrophil depletion attenuated the interleukin-8 increase in the lung. Large Vt did not increase plasma interleukin-8 or tumor necrosis factor-alpha in plasma and bronchoalveolar lavage fluid. No expression of p-selectin or intercellular adhesion molecule-1 was observed. CONCLUSIONS: Cyclic overstretching of normal rabbit lungs with noninjurious large Vt produced neutrophil influx and interleukin-8 increase in bronchoalveolar lavage fluid. Production of pulmonary interleukin-8 by lung overstretch might require the interaction between resident lung cells and migrated neutrophils. This study suggests that large Vt ventilation potentiates the predisposed, subclinical lung injury, such as nosocomial pneumonia or aspiration of gastric contents.     

Effect of the Mueller manoeuvre at different lung volumes on left ventricular performance in normal subjects

Summary. The effect of reduced intrathoracic pressure at different lung volumes on cardiac function was assessed by echocardiographic measurements of left ventricular size in normal subjects who performed the Mueller manoeuvre at two preselected lung volumes. At functional residual capacity (FRC), both mean end-diastolic dimension and mean end-systolic dimension increased (5·1±0·4 to 5·4±0·5 cm; P<0.001 and 3·7± 0·4 to 3·9± 0·4 cm; P<0·025, respectively). At high lung volume (HLV), midway between FRC and total lung volume, mean end-diastolic dimension increased from 5·1±0·5 to 5·3±0·5 cm (P<0·001), less than the increase at FRC, and mean end-systolic dimension increased from 3–520.4 to 3·9±0·4 cm (P<0–001), similar to the increase at FRC. Thus, mean stroke dimension and shortening fraction were reduced at HLV (1·5 ± 0·2 to 1·3 ± 0·2 cm and30 ± 4to26 ± 2% respectively, P < 0·025). At FRC and HLV respectively, mean left ventricular transmural pressure increased from 111 to 129 Torr (P<0·001) and from 111 to 128 Torr (P<0·001) in response to the Mueller manoeuvre, although intraesophageal (intrathoracic) pressure was significantly lower (P < 0·001) during the Mueller manoeuvre at HLV. These results show that lung volume affects the left ventricular response to the Mueller manoeuvre. Furthermore, the changes in left ventricular dimensions induced by the Mueller manoeuvre are determined by the level of reduced intrathoracic pressure, through differing effects on left ventricular afterload and filling.     

胆总管十二指肠下腔静脉区正常淋巴结的超声表现

目的 观察正常人群中胆总管十二指肠下腔静脉区（ＣＤＣ）淋巴结的超声表现。方法 随机选择经临床各种方法检查未发现异常的正常人２７８例,超声扫查ＣＤＣ区淋巴结。     

Duodenal bulb pH in normal subjects

Four pH electrodes strapped together at 1 X 5 cm intervals were positioned in the pyloric region. Electrodes situated in the stomach record steady acid pH while electrodes distal to the pylorus show fluctuating pH, thereby enabling the electrodes to be localized from the pH pattern. Digital pH values were sampled and stored at a rate of 2/s from each electrode. For each 10-min period, the mean hydrogen ion activity, the percentage of time that the pH was at less than 3.0 and number of pH spikes were computed. Fourteen healthy subjects were studied in the fasting state and for 3 h after 300 ml chocolate milk. Log mean hydrogen ion activity in the proximal part of the duodenal bulb was (median and interquartile range): fasting pH 2.40 (2.23-3.00); 0-60 min after meal: pH 5.7 (4.92-5.95); 60-120 min: pH 2.31 (1.95-3.20) 120-180 min: pH 2.20 (1.99-2.44). Repeated studies in twelve subjects showed a linear correlation between 1st and 2nd study, r = 0.87. A significant linear correlation was found between peak acid output to pentagastrin and postprandial bulb acidity.     

Theophylline pharmacokinetics in normal elderly subjects

The effect of age on theophylline kinetics was examined in six normal young men and six elderly men. There were no age-associated differences in theophylline volume of distribution, total clearance, or t1/2. The unbound fraction of theophylline was significantly raised in the elderly (mean 77.7% vs. 62.3%, p less than 0.001) and was correlated with the serum albumin level (r = -0.7, p less than 0.01). Theophylline nonrenal clearance was not changed, but the total unbound clearance was significantly reduced in the elderly subjects as compared with the young ones (mean 0.744 vs. 1.085 ml/min/kg, p less than 0.05). Creatinine clearance was reduced in the elderly and was significantly correlated with unbound renal clearance (r = 0.6, p less than 0.04). There were no age-related differences in the urinary excretion of theophylline, 1-methyluric acid, 3-methylxanthine, or 1,3-dimethyluric acid. However, significant reduction in unbound renal theophylline clearance (p less than 0.002) as well as the unbound metabolic clearance of 1,3-dimethyluric acid (p less than 0.03), 3-methylxanthine (p less than 0.04), and 1-methyluric acid (p less than 0.02) were observed in the elderly subjects. These observations indicate that both renal and metabolic elimination processes for theophylline are less active in the normal elderly.     

Multiple-dose ciprofloxacin kinetics in normal subjects

To determine multiple-dose kinetics of the quinoline carboxylic acid derivative ciprofloxacin, we gave 12 normal subjects ciprofloxacin, 250 mg by mouth every 12 hr for 13 doses. Plasma concentrations were measured by HPLC after the first, seventh, and thirteenth doses. Peak and trough plasma concentrations were measured daily. Ciprofloxacin was rapidly absorbed from the gastrointestinal tract and reached maximum serum concentrations about 1 hr after dosing. Ciprofloxacin elimination t1/2 increased from 3.71 hr after the first dose to 6.51 hr after the thirteenth dose (P less than 0.05). Apparent plasma clearance decreased from 0.823 to 0.629 l/kg/hr because of decreased nonrenal clearance. Drug cumulation did not occur throughout the experiment. We conclude that concentrations of ciprofloxacin in excess of the minimum inhibitory concentrations for many important pathogens can be achieved in plasma and that controlled clinical trials of ciprofloxacin efficacy in selected systemic infections are warranted.     

Plasma fibronectin concentration in normal subjects

The plasma concentration of fibronectin was determined in 374 normal subjects, newborn to 85 years of age, by quantitative electroimmunoassay. The plasma fibronectin concentration was higher in males than in females and the concentration increased with age. No day to day or diurnal variation was found. Different stabilizers of blood did not influence the results.     

The excretion of oxypurines in normal subjects

Reverse phase high performance liquid chromatography was used for the determination of urinary hypoxanthine and xanthine in normal subjects. The values observed in normal subjects agree with those reported by other authors. Excretion of hypoxanthine and xanthine was not related to sex. Urinary oxypurines were related to age, and, when corrected for body surface area (1.73 m2), they were significantly higher in normal children under 15 years of age than in adults.     

Absolute bioavailability of amiodarone in normal subjects

The relative and absolute bioavailability of different oral forms of amiodarone was examined in 12 subjects. The doses were 5 mg/kg iv, two 200-mg commercial tablets by mouth, two 200-mg tablets (new formulation) by mouth, and 400 mg in a drinkable solution. Plasma levels of amiodarone and its N-desethylated metabolite were determined by HPLC. Statistical analysis indicated bioequivalence of the oral forms for all the kinetic parameters examined. After oral dosing, amiodarone was slowly absorbed and the maximum plasma level (0.55 +/- 0.20 mg/l) was reached in 4.5 hr. The absolute bioavailability of oral amiodarone was calculated by comparison of AUCs after oral dosing with those after intravenous injection. A mean oral bioavailability of 65% +/- 22% was indicated. Since the tablets were bioequivalent to the drinkable solution, incomplete absorption seems not be a result of the dissolution characteristics of the commercial formulation but rather of a first-pass effect.     

Pharmacokinetics of oxprenolol in normal subjects.

The effect of oxprenolol administered intravenously (10 and 20 mg) and orally (20, 40, 80, and 160 mg) on plasma concentrations of the drug, resting heart rate, exercise-induced tachycardia, and arterial blood pressure was assessed as a function of time in 6 healthy subjects. The pharmacokinetics of oxprenolol following intravenous administration are best described as 2-compartnent open model with dose-dependent parameters. The mean (+/-SD) plasma half-life for oral doses is 1.94 +/- 0.37 and for intravenous doses is 2.31 +/- 0.64 hr. After oral administration, peak plasma concentrations are reached within 30 to 90 min, and the area under the plasma concentration-time curve varies linearly with the dose. Comparison of oral and intravenous data reveals the variation in bioavailabilty of orally administered oxprenolol to range from 19% to 74%. Unlike propranolol, oxprenolol does not show a saturable "first-pass" elimination effect. Blockade of beta-receptors occurs at plasma levels in excess of 60 ng/ml as evidenced by significant reductions in resting heart rate and exercise-induced tachycardia. Higher plasma concentrations of oxprenolol are required to lower blood pressure compared to those necessary to slow heart rate. These data suggest significant pharmacokinetic differences between oxprenolol and other beta-adrenergic receptor antagonists.