Biomedical subjects

M B Lima

Publications and source records attributed to M B Lima.

15 recordsLinked to original sources

PubMed1998

Changes in renal hemodynamics and tubular function of surgically cured primary hyperparathyroid patients are probably due to chronic hypercalcemic nephropathy.

To understand the mechanisms responsible for the persistent hypercalciuria and reduced glomerular filtration rate (GFR) previously found in 6 of 10 patients surgically cured of primary hyperparathyroidism (PHPx), the tubular handling of lithium, sodium, calcium, and phosphate as well as the renal hemodynamics were evaluated in these 10 PHPx patients, in 10 control subjects, and in 5 patients with renal hypercalciuria (RH), during fasting and after an oral calcium load. A positive correlation between the fractional excretions of calcium and sodium was found in all groups, but the PHPx patients excreted more calcium for the same amount of sodium than control subjects. The fractional proximal sodium reabsorption (FPRNa), distal delivery, and fractional phosphate reabsorption were similar in all groups; a significant positive correlation was found between the fractional calcium reabsorption and the FPRNa, indicating that proximal tubular function was preserved and that the urinary calcium losses in RH and in the hypercalciuric PHPx patients (h-PHPx) occurred in the distal nephron. However, only h-PHPx patients had reduced renal plasma flow, renal blood flow, and GFR, as well as a high renal vascular resistance, which was even more evident after the calcium challenge. These findings lead us to conclude that RH and h-PHPx patients are very different, as far as kidney dysfunction is concerned, and that a hypercalcemic nephropathy is the most probable cause of the alterations in distal calcium reabsorption and renal hemodynamics found in the h-PHPx patients.

Adenoma↗

PubMed1996

The cause of maintained hypercalciuria after the surgical cure of primary hyperparathyroidism is a defect in renal calcium reabsorption.

The hypercalciuria that eventually remains after the successful removal of a solitary parathyroid adenoma may originate from excessive intestinal calcium absorption, bone resorption or deficient renal reabsorption. In order to clarify this question, ten patients surgically cured from primary hyperparathyroidism (PHPx), ten age-matched normal subjects and five nephrolithiasic patients with renal hypercalciuria (RH) were studied after five days on a low calcium diet, either during fasting or after oral calcium load. Fasting serum calcium, amino-terminal and intact PTH levels and also urinary cAMP excretion were normal in every individual patient. Serum ionized calcium and inulin clearance (GFR) were used for calculations of the filtered load (FL Ca) and the fractional excretion of calcium (FE Ca). Six PHPx patients displayed fasting calciuria above the upper limit calculated for control subjects, despite having the lowest GFR and FL Ca (p < 0.05 vs control). These patients (h-PHPx) had a small calciuric response to oral calcium load. Serum 1,25-(OH)2D3 and 25OHD3 did not correlate with calciuria. Our findings exclude intestinal hyperabsorption and excessive bone resorption in h-PHPx patients, and strongly suggest a renal tubular defect in calcium reabsorption as the cause of their hypercalciuria. This defect could be primary, as in RH, but only three hPHPx patients had recurrent kidney stones before surgery. On the other hand, as a negative correlation between GFR and FE Ca was only found in PHPx patients, it seems probable that the disturbances in glomerular and tubular functions were secondary to the long standing hypercalcemic hyperparathyroidism.

Adenoma↗

PubMed1990

Trends in bacterial resistance and implications for treatment of infections.

The development of resistance to antibiotics can present a major problem when treating serious bacterial infections. Resistance may be increased due to indiscriminate prescribing and variations in resistance to an antibiotic may reflect different prescribing habits. In Latin American countries, where use of antibiotics is poorly controlled, resistance to gentamicin, tobramycin and amikacin, for example, is considerably higher than that found in Europe and the USA, where tighter restrictions are imposed. It is concluded that vigilance in the prescribing of antibiotics should be observed to prevent further increases in resistance.

Aminoglycosides↗

PubMed1984

Cushing's disease: clinical and laboratory response to bromocriptine therapy.

Four patients with Cushing's disease were treated with bromocriptine, administered three times daily, in doses ranging from 7.5 to 15 mg/day, during an average period of 80 days. Daily urinary 17-hydroxycorticosteroids (17-OHCS) and 17-ketosteroids (17-KS) excretion was measured during dynamic tests and at two-week intervals. Plasma adrenocorticotropic hormone (ACTH) and cortisol levels were also assayed before and after therapy. A marked clinical and laboratory improvement was noted in two patients, in another some clinical and laboratory improvement was obtained only after bromocriptine dosage was increased to 15 mg/day. There was no effect in the fourth patient. Thus, at least for a short period of time, bromocriptine may be useful therapy for some patients with Cushing's disease.

17-Hydroxycorticosteroids↗

PubMed1975

A new treatment for hirsutism.

Twenty-four hirsute female patients were treated with 100 mg of depo-medroxyprogesterone acetate intramuscularly every 15 days. Twenty-three showed definite improvement from their abnormal hair growth. All patients with initially elevated 17-ketosteroids in 24-hour urine collections showed a decrease of these metabolites with treatment. In eleven patients the initial plasma testosterone level was elevated and returned to normal values with treatment. The first patient who was submitted to this therapy stopped the treatment for 5 months and started having abnormal hair growth again. With other patients, after initial treatment with depo-medroxyprogesterone acetate intramuscularly, we started using contraception pills containing medroxyprogesterone; this maintained the reduced ectopic hair growth. The most important side effect was amenorrhea.

Adolescent↗

PubMed1972