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Biomedical subjects

T Tulassay

Publications and source records attributed to T Tulassay.

At least 145 records · Page 8Linked to original sources

Tubular dysfunction in type I diabetes mellitus.

Tubular function was investigated in patients with diabetic ketoacidosis and those with poorly controlled type I diabetes. Urinary excretion of beta 2 microglobulin and that of certain enzymes: gamma glutamyltransferase, leucine aminopeptidase, and N-acetyl-beta-D-glucosaminidase activities were significantly raised during ketoacidosis in 11 patients compared with healthy controls. In 13 poorly controlled diabetics, tubular electrolyte transport was studied and a significant reduction in tubular phosphate and sodium reabsorption was found. Tubular dysfunction occurring during diabetic ketoacidosis and in poorly controlled diabetics may contribute to the development of diabetic nephropathy.

Adolescent↗

Effect of low-dose dopamine infusion on prolactin and thyrotropin secretion in preterm infants with hyaline membrane disease.

The effect of low-dose (2-4 micrograms/kg/min) and long-term (greater than or equal to 46 h) dopamine infusion on serum prolactin and thyrotropin concentrations was investigated in 8 preterm infants with hyaline membrane disease. Dopamine was administered for systemic hypotension and/or for impending renal failure. Serum prolactin decreased from 1,314.5 +/- 422.7 microU/ml to 489.9 +/- 464.1 microU/ml (p less than 0.005), while serum thyrotropin fell from 3.77 +/- 2.27 microU/ml to 1.01 +/- 0.25 microU/ml (p less than 0.025) during dopamine infusion. Our data indicate that exogenous dopamine exerts an inhibitory effect on the secretion of prolactin and thyrotropin even in the sick preterm neonate. The role of prolactin in fetal lung maturation and in regulation of the neonatal tissue water stores is discussed. The results of the present study are also useful in explaining the renal effects of long-term low-dose dopamine infusion in the sick preterm infant.

Dopamine↗

Cardiovascular response to dopamine in hypotensive preterm neonates with severe hyaline membrane disease.

The effect of low dose (2, 4, and 8 micrograms/kg per min) dopamine infusion on blood pressure, heart rate and renal function was studied in 18 hypotensive, preterm infants with severe hyaline membrane disease (HMD). Significant dose-related effects found during dopamine infusion were systolic and diastolic blood pressure elevation and diuretic effect, while heart rate increase occurred only with 8 micrograms/kg per min of the drug. This indicates, that in the preterm neonate, dopamine at low doses has a pronounced effect on the alpha- and dopamine-receptors, while its beta-receptor stimulating activity is minimal. We demonstrated a significantly decreased metabolic clearance rate of dopamine in preterm infants. Thus, beside the differences in the vascular receptors' maturation, the decreased metabolic clearance rate should also be taken into account when explaining the cardiovascular and renal effects of low dose dopamine infusion in these babies. Dopamine was found to be useful in normalizing low arterial blood pressure, in improving impaired peripheral circulation, and in producing a marked diuresis in hypotensive preterm neonates with severe hyaline membrane disease.

Blood Pressure↗

The use of dopamine for the prevention of the renal side effects of indomethacin in premature infants with patent ductus arteriosus.

To determine if dopamine would prevent the renal side effects of indomethacin, fifteen preterm infants were randomized into two groups: seven received indomethacin alone, and eight received indomethacin together with low dose dopamine infusion. Infants who received indomethacin together with dopamine had significantly higher UV (p less than 0.005), CNa (p less than 0.005), Cosm (p less than 0.005) and FENA (p less than 0.005) than those of infants who received indomethacin alone. There was, however, no significant difference in Ccr and FNa between the groups. These data indicate that dopamine overcomes indomethacins renal side effects of tubular origin, but it cannot prevent the renal vasoconstrictive action of vasoconstrictor hormones following the inhibition of prostaglandin synthesis by indomethacin. Considering that RBF and GFR turn to normal approximately 12 hours after the last dose of indomethacin, and that with the use of dopamine systemic blood pressure and peripheral circulation can also be normalized and to some extent myocardiac contractility improved, low doses of dopamine can be used instead of furosemide in the sick preterm infant with PDA when indomethacin therapy is indicated.

Clinical Trials as Topic↗

Effects of continuous positive airway pressure on renal function in prematures.

The effects of continuous positive airway pressure respiratory therapy--used in centrencephalic apnea in premature infants--has been investigated at a value of +6 cm H2O end-expiratory pressure. The results showed a significantly decreased glomerular filtration rate, decreased sodium and hydrogen ion excretion and urine output, without changes in systemic blood pressure, pulse rate, and blood gas values. At +3 cm H2O end-expiratory pressure no changes were observed.

Apnea↗

Effects of dopamine on renal functions in premature neonates with respiratory distress syndrome.

The renal effects of dopamine have been studied in preterm infants with RDS. Dopamine has been given in doses of 0.5-2.0 microgram/kg/min as a continuous intravenous infusion in cases of peripheral circulatory disturbances. As a result, the circulation became stable and some renal parameters improved. There was a + 106% increase of urine output as well as a + 73%, + 140%, + 21% increase in Na-excretion, FeNa, creatinine clearance respectively. In accordance with the marked increase in phosphorus excretion the titratable acidity was also increased. There was a significant decrease in the renal urea excretion and free water clearance. These alterations were probably caused by an intrarenal hemodynamic redistribution. The possible mechanism of the renal changes are also discussed. The observations demonstrate the functional maturity of renal dopaminergic receptors in the preterm infants.

Dopamine↗

[Effects of furosemide on renal functions in prematures (author's transl)].

Renal effects of Furosemide were examined during the first 2-4 days of life in preterm infants suffering from respiratory distress syndrome. Administration of the drug was followed by a sevenfold increase of diuresis. This latter was a result of both a rise in sodium excretion and glomerular filtration. The possible mechanism of Furosemide induced alteration in the glomerular filtration is discussed. Furosemide also altered the hydrogen-ion excretion: both the urinary bicarbonate, the titratable acidity and the ammonium excretion increased. There was a significant rise in the net acid excretion and hydrogen clearance too. It has been found that besides its diuretic effect Furosemide might play a role in the renal hydrogen elimination.

Acid-Base Equilibrium↗