ABSTRACT
This study examined the effects of acute administration of bleomycin (BLM) on lung liquid and protein exchange in anesthetized sheep prepared with caudal mediastinal lung lymph fistulas. Six sheep received BLM (15 U IV) after a baseline period, while seven others were given BLM after a steady state was obtained following elevation of left atrial pressure (PLA), a procedure intended to minimize changes in pulmonary microvascular surface area and produce high lung lymph flow (QL). Plasma and lung lymph angiotensin converting enzyme (ACE) activities were measured in order to independently assess the effects of BLM on pulmonary endothelial integrity. QL rose significantly in all animals following BLM. The ratio of lymph to plasma protein concentration (CL/CP) did not change in the group given BLM alone, and fell continuously during the period of PLA elevation after BLM in that group. Plasma and lung lymph ACE activities were unchanged following BLM administration in either group. The ultrastructure of the gas-exchanging region of lungs from animals in each group was examined by transmission electron microscopy. The data suggest that acute administration of a low dose of BLM does not increase pulmonary microvascular permeability, but may induce an increase in perfused pulmonary microvascular surface area responsible for increased QL.
Subject(s)
Bleomycin/toxicity , Lung/drug effects , Lung/physiopathology , Water-Electrolyte Balance/drug effects , Acetylcholinesterase/metabolism , Animals , Biological Transport, Active/drug effects , Bleomycin/administration & dosage , Capillary Permeability/drug effects , Capillary Permeability/physiology , Hemodynamics/drug effects , Hemodynamics/physiology , Lung Injury , Lymph/drug effects , Lymph/physiology , Microcirculation/drug effects , Microcirculation/physiology , Proteins/metabolism , Pulmonary Gas Exchange/drug effects , Pulmonary Gas Exchange/physiology , Sheep , Water-Electrolyte Balance/physiologyABSTRACT
Although the incidence of Reye's syndrome is declining, it remains a deadly disease. Early recognition and initiation of supportive measures can decrease the mortality rate from this disorder. Glucose levels should be maintained and electrolyte imbalances and coagulopathies should be corrected in patients with early Reye's syndrome. Comatose patients require specialized care at a tertiary care facility that has the capability to prevent and treat intracranial hypertension. Survivors of Reye's syndrome may have subtle neuropsychologic deficits but generally recover very well considering the gravity of the disease.
Subject(s)
Reye Syndrome/diagnosis , Child , Diagnosis, Differential , Female , Humans , Reye Syndrome/mortality , Reye Syndrome/therapyABSTRACT
We prepared nine sheep with acute tracheobronchial afferent (TBN) and caudal mediastinal efferent (CMN) lymph fistulas. After a baseline period (B) in 3 sheep, we administered histamine (H) continuously for 4 h. In six sheep, we elevated left atrial pressure (PLA) and reestablished steady-state conditions prior to H administration. The afferent lymph to plasma protein concentration ratio (CA/CP) was significantly lower than the efferent ratio (CE/CP) during periods of B, H, elevated PLA, and elevated PLA with H. H administration increased lymph flow rates (QlA and QlE) and both CA/CP and CE/CP, albeit insignificantly. During elevated PLA, QlA and QlE increased, while CA/CP and CE/CP fell. QlE increased, while QlA did not change during elevated PLA with H. CE/CP increased from its PLA level. CA/CP did not increase. Afferent data suggest that histamine may increase pulmonary microvascular surface area, but does not alter the permeability of the pulmonary circulation. While we cannot exclude the possibility of an increase in pulmonary microvascular permeability from efferent results, the difference between TBN afferent and CMN efferent results likely represent the action of histamine at the CMN.
