Search PubMed⌕ Search

Biomedical subjects

J G de Carvalho

Publications and source records attributed to J G de Carvalho.

11 recordsLinked to original sources
PubMed1989

[Intraerythrocytic potassium and diuretic therapy].

Diuretic-induced hypokalemia is one of the most common and important disturbances during antihypertensive therapy. However, it has been suggested that determination of serum potassium levels may not reflect significant changes of its intracellular concentration. This study was performed to evaluate whether there is any change of red cell potassium concentration as compared to serum potassium levels, in ten patients receiving chlorthalidone, 25 mg/day, during 4 weeks. Significant antihypertensive effect was achieved and despite serum potassium levels less than 3.5 mEq/1 occurred in four patients, no significant change in intracellular concentration of potassium was observed in this population with essential hypertension.

Adult↗
PubMed1980

Reaction of glutaraldehyde with human erytrocytes.

The reaction of glutaraldehyde with human erythrocytes has been studied at pH values of 6.0, 7.2 and 8.0 at several glutaraldehyde concentrations, for different periods at 37 degrees C. Increasing pH and reagent concentration favours formation of cells resistant to osmotic and chemical (by n-butanol, saponin and sodium dodecyl sulfate (SDS)) hemolysis. Ultrasonic waves also have no effect upon these cells. Different behavior concerning the state of hemoglobin, K+ efflux, and swelling have also been observed, according to the pH of treatment. The results suggest that crosslinking involving hemoglobin molecules and components of the membrane (proteins, aminophospholipids) may be obtained in the reaction of human erythrocytes with glutaraldehyde.

Aldehydes↗
PubMed1978

Ticrynafen: a novel uricosuric antihypertensive natriuretic agent.

Interest in new diuretics with less side effects has led to the synthesis of ticrynafen, an uricosuric diuretic. This agent was compared with hydrochlorothiazide in a crossover design study involving 12 hypertensive men. Both agents significantly decreased mean arterial pressure from 8% to 18% in eight of the 12 patients. In addition to reducing body weight, these diuretics induced reversible changes in BUN and carbon dioxide content (increased) and plasma concentration of potassium and chloride ions (decreased). The most important change in renal function was a 2.5-fold increase in fractional urate clearance by ticrynafen associated with reduction of serum uric acid by 62%. Thus, ticrynafen is a promising therapeutic agent in hypertension, adding a unique uricosuric effect that should improve patient compliance.

Blood Pressure↗
PubMed1978

Hemodynamic, reflexive, and metabolic alterations induced by acute and chronic timolol therapy in hypertensive man.

The hemodynamic, cardiovascular, and metabolic effects of acute (intravenous) and prolonged (four weeks oral) timolol treatment were assessed in 16 patients with mild or moderate essential hypertension. Fifteen patients completed the outpatient study and ten showed a fall in mean arterial pressure of at least 10 mm Hg. They also demonstrated a significant fall in supine systolic (7%), diastolic (9%), and mean arterial pressure. Hemodynamic evaluation was performed in 13 patients and cardiac index was found to be reduced with both intravenous (20%) and oral timolol (13%). There was no correlation between the decrease in cardiac index and arterial pressure. Calculated total peripheral resistance rose with intravenous timolol and returned toward, but not below, pretreatment values with the oral therapy. Left ventricular ejection rate also fell significantly with intravenous timolol but returned toward pretreatment levels with oral therapy. Plasma renin activity was reduced similarly with both modes of administration and its reduction also did not correlate with the fall in arterial pressure. Plasma volume fell in eight of 13 patients. Reflexive responses to the Valsalva maneuver were considerably modified by both intravenous and oral timolol but responses to 50 degrees upright tilt and handgrip were not. Timolol is an effective oral antihypertensive agent with similar hemodynamic and metabolic effects to propranolol.

Administration, Oral↗
PubMed1978

Hemodynamic correlates of saralasin-induced arterial pressure changes.

Angiotensin antagonists have proved useful in elucidating the clinical role of the renin-angiotensin system; and their diagnostic and therapeutic efficacy in hypertension has been the subject of many reports but the hemodynamic effects remain unknown. Therefore, saralasin was infused intravenously (1.3 mg/min for 30 min) in 26 sodium-depleted patients with hypertension. Systemic hemodynamic alterations were determined before, during, and after infusion. On the basis of mean arterial pressure (MAP) changes, patients were classified as responders, nonresponders, or pressorresponders (MAP changes greater than or equal to 10 mm Hg). MAP fall in responders was achieved through reduced cardiac output and/or total peripheral resistance, with minimal or absent reflexive heart rate increase. In nonresponders, despite no change in MAP, output fell in parallel with stroke index and left ventricular ejection rate, In pressorresponders, saralasin increased vascular resistance. Thus, in addition to variable effects on vascular receptors, saralasin produced inhibitory cardiac effects either through altered venous return or inhibition of contractility.

Adult↗