Comparative effects of adrenaline as a hormone on airway conductance, plasma glucose, pulse rate and blood pressure in normal subjects.
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Biomedical subjects
Publications and source records attributed to N Dalton.
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The circulatory, renal, and hormonal responses to physiological elevation of plasma insulin induced with oral glucose have been studied in seven healthy subjects. glomerular filtration rate, urinary excretion rates of albumin and Beta2-microglobulin, haematocrit, pulse rate, blood pressure and plasma catecholamine concentrations have been measured. Physiological hyperinsulinaemia following glucose ingestion was associated with an increase in noradrenaline levels and brief tachycardia. No effect was noted on haematocrit, creatinine clearance, urinary albumin excretion, plasma adrenaline concentrations and arterial blood pressure. Urinary Beta2-microglobulin excretion rates fell shortly after the elevation of plasma insulin, probably indicating enhanced tubular reabsorption. Thus, glucose-induced physiological hyperinsulinaemia does not reduce glomerular filtration rate nor does it increase transglomerular passage of albumin, effects seen after the intravenous bolus injection of 6-8 U of insulin in diabetics.
Protein malnutrition is common in children with chronic renal failure (CRF) and is especially severe in young infants. Growth is usually rapid in infants and CRF causes a reduction in cell mass associated with extreme growth retardation in this age group. Poor energy intake and altered energy metabolism are common in CRF and are associated with protein malnutrition and poor growth. Uraemic toxicity may reduce protein synthesis by altering energy metabolism or by a direct effect, low protein high energy diets improve growth and extremely low nitrogen intakes supplemented with essential amino acids and keto acids may be useful in selected children.
The effects on growth, nitrogen balance, and body composition of a protein-restricted diet supplemented with oral essential amino acids (EAA) were studied in seven children with advanced chronic renal failure. The diet was designed to provide minimum protein requirements for height-age, half in unselected form and half as an EAA supplement. Energy from carbohydrate and fat were increased to give a protein/energy ratio of 1.25 G:100 kcal. Nitrogen balance, studied in five children before and after 6 to 8 months of EAA treatment, was improved in each case. intracellular water (total body water minus bromide space) increased in four children but fell in three children during treatment. No significant improvement in growth, expressed as height or height velocity standard deviation scores in relation to bone age, was observed. Serum urea and urea/creatinine ratio fell after institution of EAA treatment, but the fall was not sustained. Although the EAA preparation proved acceptable to the children, dietary assessments indicated that the desired dietary aims were rarely achieved. It is concluded that, in this pediatric age group, the long-term application of a protein restricted diet with EAA supplements is of limited value.
Color flow Doppler mapping using either an Aloka 880 or a Toshiba SSH65A system was performed in 39 normal subjects (aged 13 to 45 years) and 43 patients (aged 13 to 82 years) with pathologic tricuspid or pulmonary regurgitation to evaluate the incidence of "physiologic" regurgitation of right heart valves and to determine the differentiating characteristics in the spatial distribution and velocity encoding of "normal" and "pathologic" regurgitant jets. In the normal subjects, tricuspid and pulmonary regurgitation were documented in 32 (83%) and 36 (93%), respectively, and were unrelated to the system being used. Flow acceleration and aliasing were imaged on the right ventricular side of the tricuspid regurgitant orifice and on the pulmonary artery side of the pulmonary valve (in both normal subjects and patients), and indicated flow convergence for true regurgitation through an orifice as opposed to blood being driven retrogradely by the closing valve. Such proximal acceleration was documented in all patients with pathologic tricuspid regurgitation, in 31/32 of the normal subjects with tricuspid regurgitation, and was also observed in 12/15 (80%) of the patients and 4/12 (33%) of normal subjects with pulmonary regurgitation who were examined with the Toshiba system. The dimensions (mean +/- SD) of tricuspid regurgitant jets (length [JL] and area [JA]) were consistently larger in the patients than in the normal subjects [JL: 3.4 +/- 0.9 vs 1.2 +/- 0.5 cm, p less than 0.001; and JA: 5.7 +/- 2.0 vs 1.4 +/- 0.7 cm2, p less than 0.001) as were the pulmonary regurgitation jet dimensions (JL: 1.8 +/- 0.4 vs 0.9 +/- 0.08 cm, p less than 0.001; JA: 1.8 +/- 0.7 vs 0.3 +/- 0.08 cm2, p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)
The current concept of ventricular filling in elasmobranch and teleost fishes is that atrial contraction is the primary, if not the exclusive, determinant of ventricular filling. Recent echocardiographic and on-line hemodynamic data for elasmobranchs, however, have demonstrated a biphasic ventricular filling pattern, characterized by an early phase that occurs during ventricular relaxation and a late phase that follows atrial systole. This study reports echocardiographic and hemodynamic analyses of ventricular filling in three teleost genera (Paralabrax, Channa, Monopterus) having markedly different heart morphologies. Both the profiles of the atrioventricular pressure gradient in Paralabrax and the ventricular inflow velocity in all three genera indicate a biphasic ventricular filling pattern. Although the relative contribution of the early and late filling phases differed among the species studied, interspecific differences in heart structure did not obscure the biphasic pattern. Also, pericardiectomy did not affect the biphasic ventricular filling pattern in Paralabrax. The presence of biphasic filling in teleosts establishes a functional similarity with the elasmobranchs and, because the biphasic ventricular filling pattern predominates in higher vertebrates, suggests that this ventricular filling mechanism may be present in the entire subphylum Vertebrata.
Eleven insulin-dependent diabetic patients were treated in random order by 2-mo continuous subcutaneous insulin infusion (CSII) or 2-mo conventional injection treatment (CIT) with crossover to the alternative regimen. Mean plasma glucose concentrations throughout the day were significantly lower during CSII than during CIT, but the percentage of plasma glucose values less than 2.5 mmol/L, obtained from outpatient self-collected diurnal profiles, was similar for both treatments (CSII vs. CIT: 5.9 and 4.8%, respectively). Reported symptomatic hypoglycemia at home was not significantly different in the whole group of patients treated by CSII or CIT but was reduced by a mean of 57% (P less than .02) in the five patients on CSII who experienced frequent symptomatic hypoglycemic episodes (greater than 4/2 mo) during CIT. Neither the plasma glucose concentration at which the patients recognized induced hypoglycemia nor the glycemic or counterregulatory hormone responses for 60 min thereafter were changed by CSII treatment.