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Biomedical subjects

F Baldoni

Publications and source records attributed to F Baldoni.

At least 37 records · Page 2Linked to original sources
PubMed1987

Pure pancreatic juice collection over 24 consecutive hours.

We collected pure pancreatic juice during an entire day and examined pancreatic secretory changes induced by ordinary meals in a male patient having an external drainage of the main pancreatic duct. The ingestion of breakfast, lunch, and dinner each caused a marked increase in pancreatic secretion above basal levels. The increase in both bicarbonate and protein output was very prolonged. The highest secretory outputs induced by meals were slightly higher than those produced by exogenous administration of submaximal doses of secretin and cerulein. The profile and magnitude of bicarbonate and protein secretion were similar.

Bicarbonates↗
PubMed1986

Stimulation of exocrine pancreatic secretion by met-enkephalin.

The effect of met-enkephalin on pure exocrine pancreatic secretion was studied in five subjects with external transduodenal drainage of the main pancreatic duct carried out after biliary tract surgery. Intravenous infusion of a low dose of met-enkephalin (0.15 micrograms/kg/h) during submaximal pancreatic stimulation with secretin (25 ng/kg/h) and cerulein (10 ng/kg/h) significantly increased pancreatic outputs. Bicarbonate secretion increased 50% above control values, a more marked effect than the increase in enzyme secretion (maximal rise averaged 22%). The effect of the peptide was rapid, persisted for the duration of met-enkephalin infusion and then tended gradually to diminish.

Bicarbonates↗
PubMed1985

Cardiorespiratory reflexes from muscles during dynamic and static exercise in the dog.

Cardiorespiratory reflex responses during the initial phase of dynamic and static contraction of hindlimb muscles were studied in anesthetized dogs. Muscle contractions were elicited by stimulating the femoral and gastrocnemius nerves at 3 and 100 Hz with the intensity of 2.0-2.5 times the motor threshold for a 20-s period. Rhythmic contractions caused a decrease in arterial pressure (Pa) and heart rate (HR) and increased pulmonary ventilation (VE) by increasing frequency (f) without significantly changing VT. Tetanic contractions provoked an increase in Pa and HR and a hyperpnea resulting from a rise in both f and VT. Similar responses were also obtained in anesthetized dogs with carotid sinuses denervated and cervical vagi cut. The abrupt increase in VE at the start of both types of exercise was not associated with immediate significant decreases in end-tidal CO2 values. These two patterns of cardiocirculatory and respiratory responses were closely similar to those reported in anesthetized rabbits in previous studies. Both patterns of responses were reflexes initiated by activation of muscle receptors verified by interrupting the afferents from the contracting muscles. It is concluded that, during dynamic and static work, two distinct muscular reflex mechanisms might exert their drives, related to the muscular metabolic rate, on the circulatory and respiratory function.

Animals↗
PubMed1983

Different patterns of respiratory reflexes originating in exercising muscle.

In anesthetized rabbits, rhythmic contractions of the gastrocnemius muscle elicited by stimulating the gastrocnemius nerves (40 trains/min of 0.5-ms rectangular pulses at 2.0-2.5 mult of motor threshold), increased pulmonary ventilation by increasing frequency (f). Expiratory duration (TE) was greatly reduced, while inspiratory time (TI) was much less changed. Mean expiratory flow (VT/TE) was increased consistently more than mean inspiratory flow (VT/TI). Arterial pressure (Pa) and heart rate (HR) were decreased. During tetanic contractions (100 Hz, 2.0-2.5 X T) tidal volume (VT) increased considerably more and f considerably less than during rhythmic exercise, TE was shortened, and TI was only slightly affected. Pa and HR, after a transitory reduction, increased over the resting levels. Similar responses were also obtained in deafferented rabbits with carotid sinus, aortic, and cervical vagus nerves cut. These two patterns of cardiorespiratory changes were initiated by activation of muscle receptors verified by interrupting the afferents from the contracting muscles. It is concluded that, in the anesthetized rabbit, two different muscular reflex mechanisms are involved in controlling the pattern of breathing and ventilation during muscular exercise. One mechanism, predominantly activated during dynamic exercise, decreases TE and increases f, the other mechanism, mainly activated during static exercise, increases the inspiratory drive, thus increasing the depth of breathing.

Animals↗
PubMed1982

Effects of morphine on human pancreatic secretion: studies on pure pancreatic juice.

Data concerning the effects of morphine on human pancreatic secretion are fragmentary and inconclusive. In the present study, we evaluated the effects of morphine on pure pancreatic secretion in nine subjects with external transduodenal drainage of the main pancreatic duct performed after biliary tract surgery. Intravenous infusion of a small dose of morphine, 40 microgram/kg/h, during pancreatic stimulation with secretin and cholecystokinin, caused a significant increase in volume, bicarbonate, and calcium secretion, and a significant decrease in protein secretion. The stimulatory effect on water and electrolyte secretion was rapid and much more pronounced, reaching about 45-50% of the control levels, whereas the inhibition of protein output was slightly delayed and of lesser magnitude, reaching about 20-25% of the control values. Both effects were long-lasting. The addition of naloxone, potent opiate antagonist, prevented in part the effects of morphine on pancreatic secretion, suggesting that specific opiate receptors might be involved in these effects.

Adult↗
PubMed1981

[Comparative study of cardiocirculatory response and respiratory reflex to the injection of bradykinin, inorganic phosphates and prostaglandins into the femoral artery].

In 15 anesthetized rabbits the reflex changes in arterial pressure, heart rate and respiratory rate in response to injections of bradykinin inorganic phosphate and prostaglandins into femoral artery have been studied. Intraarterial injection of bradykinin produced a reflex fall in arterial pressure, bradycardia and tachypnea. The latency of response ranged from 6 to 7 sec. The threshold dose was about 50 ng. This effect was accompanied by a consistent increase in the afferent discharge in the saphenus nerve. Isotonic mixtures of Na2HPO4 and NaH2PO4 at pH 7, PGE1, PGE2, and PGA, when injected into femoral artery even in high doses, failed to produce any significant cardiocirculatory or respiratory reflex responses. Infusion of PGE1 (1 ug/min) into femoral artery, although inactive by itself, enhanced the reflex effect of bradykinin.

Animals↗
PubMed1981

Cardiovascular and respiratory reflexes from muscles during dynamic and static exercise.

In anesthetized and deafferented rabbits, rhythmic and static contractions of the hindlimb muscles were elicited by stimulating the femoral nerve at 3 and 100 Hz with the intensity of 2.0-2.5 times threshold for the motor fibers. Rhythmic contractions caused a decrease in systemic blood pressure, heart rate, and vascular resistance of the resting hindlimb with hyperpnea. Tetanic contractions caused a rise in arterial pressure, in vascular resistance of the nonexercising hindlimb, and in pulmonary ventilation with small increases in heart rate. These responses were not obtained after sectioning the somatic nerves of the exercised limb or when the cut central end of the femoral nerve or the intact nerve in curarized animals was stimulated with the same intensity of 2.0-2.5 times the motor threshold. Both depressor and pressor responses were, therefore, reflexes initiated in the contracting limbs. Removal of the skin from the exercising limb did not change the typical patterns of response. The most likely source of the observed reflexes is that from receptors activated by metabolites released in the exercising muscles.

Animals↗