Biomedical subjects

J Butler

Publications and source records attributed to J Butler.

At least 397 records · Page 22Linked to original sources

PubMed1975

Variability of routine pulmonary function tests.

Pulmonary function tests sometimes indicate a progressive deterioration and at other times a 'stepwise' worsening which may be followed by improvement. Interpretation depends on the extent of random or diurnal variations in function. Routing pulmonary function tests (VC, FEV1, FRC, and airway resistance (Raw)) were repeatedly measured in normal subjects, patients with stable irreversible airways obstruction, and patients with stable restrictive disease. In all groups there was a significant (P less than 0.001) diurnal variation in Raw, with high values in the morning, low values at noon, and rising values in the evening. The midday Raw values were about 80% of the highest daily values. The considerable random and diurnal variability seen in all tests is reflected in the range of high and low values (% of mean individual response) in individuals. The largest variation in an individual between measurements taken at two different times was 81% in Raw (range: 40% above to 41% below the mean). There was less variation in FEV1 (29%), FRC (62%), and VC (30%). Thus the finding of a stepwise change in function could reflect its natrual variability. When repeated studies are done to assess progress or the effects of therapy on disease, there are many factors, including the time of day at which the tests are performed, which should be standardized as far as possible.

Air Pollution↗

PubMed1975

Pulmonary venous waterfall and perivenous pressure in the living dog.

Evidence has been obtained that a waterfall effect occurs in the pulmonary veins of the living dog. Anesthetized open-chest dogs were used. Small catheters were passed from the left atrium retrogradely up the pulmonary veins and venous tributaries until they finally pierced the venous walls. They were then pulled out through the surface of the lung until their bellshaped inner ends wedged in small side branches of the vein. They were used to measure upstream venous pressures via the occluded tributary without occlusion of the vein. The pulmonary lymphatics and bronchial circulation were untouched. Alveolar pressure (transpulmonary pressure, Ptp) was held constant during the periods of measurement. We found that intrapulmonary (upstream) venous pressures did not rise with elevation of left atrial (downstream) pressures at any Ptp until a pressure of at least 7 cmH2O above the base of the lung was exceeded. This left atrial pressure (below which a venous waterfall or flow-limiting segment effect was present) increased with Ptp when Ptp exceeded about 15 cmH2O. The waterfall occurs in the larger veins at the lung surface. Its presence and location suggest that intrapulmonary veins in the living animal are held open by the surrounding lung tissue and that neither the flow through them nor their contained volume is influenced by left atrial pressure when this is low.

Animals↗

PubMed1975

Cardiac limitation to maximal oxygen transport and changes in components after jogging across the US.

Observations were made before and 3-5 days after prolonged endurance jogging an average of 42 miles/day, 6 days/wk for 2.5 mo by a young male adult who voluntarily initiated a run across the United States. Both arterial PO2 and lactic acid increased. In each instance, the first limitation in circulatory delivery of oxygen was a plateau in stroke volume and cardiac output. Afterward, pulse deficit and systemic arterial pressure fell with exercise and heart rate accelerated. Although there was no change in oxygen transport (Q X CAO2), a reduction in stroke volume was exactly balanced by a rise in arterial oxygen content. Vital capacity, residual volume, and total lung capacity and diffusion capacity for carbon monoxide, hematocrit, and red cell mass increased, while plasma volume diminished and heart size and total blood volume were unchanged.

Adult↗

PubMed1975

Effects of pattern of ventilation on pulmonary metabolism and mechanics.

Effects of three patterns of mechanical ventilation on pulmonary mechanics, lung phospholipid and surface activity were studied in the normal closed-chest dog. The patterns were continuous mechanical ventilation with: 1) tidal volume (VT)=15 ml/kg; 2) VT=15 ml/kg with 10 cm H2O positive end-expiratory pressure (PEEP); 3) VT=50 ml/kg. THE DOGS IN EACH GROUP WERE VENTILATED FOR 24 HOURS, WITH CAREFUL ATTENTION PAID TO MAINTENANCE OF NORMAL BLOOD GASES, FLUID BALANCE, AND CARDIAC OUTPUT. The animals were sacrificed and the lungs studied to determine pressure-volume curves, dry lung weight/wet lung weight ratios, phospholpid contents and surface activities. The results were compared with control values in acutely sacrificed unventilated dogs. No significant change from controls was found with any pattern of ventilation employed with the exception of the tendency for lungs ventilated with PEEP to retain fluid (decreased dry lung weight/wet lung weight ratio).

Animals↗

PubMed1975

Diagnosis of neuroblastoma by electron microscopy of bone marrow aspirates.

Three patients are reported in whom the diagnosis of neuroblastoma was made following electron microscopy of a bone marrow aspirate. The ultrastructure of neuroblastoma cells is distinctive, and they can be distinguished by electron microscopy from cells of the other tumors with which neuroblastoma is often confused by light microscopy. The rapidity with which the diagnosis can be obtained through use of this procedure argues for its adoption in any patient in whom the diagnosis is suspected and who has tumor cells in bone marrow. Early initiation of appropriate therapy is made possible, and elaborate diagnostic procedures may be avoided.

Abdominal Neoplasms↗

PubMed1974