Cardiopulmonary response to extracorporeal venous CO2 removal in awake spontaneously breathing dogs

The ventilatory response to a reduction in mixed venous PCO2 has been reported to be a decrease in breathing even to the point of apnea with no change in arterial CO2 partial pressure (PaCO2), whereas a recent report in exercising dogs found a small but significant drop in PaCO2 (F. M. Bennett et al. J. Appl. Physiol. 56: 1335-1337, 1984). The purpose of the present study was to attempt to reconcile this discrepancy by carefully investigating the cardiopulmonary response to venous CO2 removal over the entire range from eupnea to the apneic threshold in awake, spontaneously breathing normoxic dogs. Six dogs with chronic tracheostomies were prepared with bilateral femoral arteriovenous shunts under general anesthesia. Following recovery, an extracorporeal venovenous bypass circuit, consisting of a roller pump and a silicone-membrane gas exchanger, was attached to the femoral venous cannulas. Cardiopulmonary responses were measured during removal of CO2 from the venous blood and during inhalation of low levels of CO2. Arterial PO2 was kept constant by adjusting inspired O2. The response to venous CO2 unloading was a reduction in PaCO2 and minute ventilation (VE). The slope of the response, delta VE/delta PaCO2, was the same as that observed during CO2 inhalation. This response continued linearly to the point of apnea without significant changes in cardiovascular function.(ABSTRACT TRUNCATED AT 250 WORDS)     

Immunoreactive Tamm-Horsfall protein in the kidney and skin of the frog Rana temporaria

Summary Tamm-Horsfall protein (THP) is the main protein in normal human urine, and is found in the thick limb of the Loop of Henle in human kidney, and in other mammalian species. The skin of the frog, Rana temporaria, has similar physiological properties to this mammalian kidney tissue. In the present study, an immunohistological method involving an antibody to human THP was used to investigate the distribution of this distinctive protein in frog kidney and skin, and to compare its distribution with that found in the kidney tubules of rat and rabbit. THP-positive material was detected in the distal renal tubules and nephric duct of frogs, and was also located in the superificial epidermis of skin. It is suggested that its presence in amphibian skin is consistent with the hypothesis that THP is an important component of tissues that absorb sodium and chloride ions, but remain impermeable to water.     

Reviewers of the Journal of Ethology for volume 27

Journal of Ethology -     

Further Observations on Diagnosis and Management of General Practice Respiratory Illness using Simulated Patient Consultations

Twenty general practitioners co-operated in a study of the decision-making process in general practice respiratory illness. Ten simulated standard-patient consultations were used, each being included twice, once to make a decision on diagnosis and once to make a decision on management.Comparison of simulated behaviour with previous studies of observed and self-recorded behaviour showed encouraging agreement. Examination of 200 pairs of management and treatment decisions showed that fewer pieces of information were required for a management than a diagnostic decision on 111 occasions; in 43 pairs the quantity required was the same for each decision. The exact information required to make a decision on diagnosis was included in the information required to decide management on only 30 (15%) of the 200 possible occasions.When disagreement was found over management of a simulated case a decision to prescribe an antibiotic required less information than a decision not to prescribe an antibiotic.