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Biomedical subjects

F Santos

Publications and source records attributed to F Santos.

At least 91 records · Page 5Linked to original sources
PubMed1991

Growth hormone metabolism in uremia.

The influence of chronic renal failure (CRF) on growth hormone (GH) and insulin-like growth factor I (IGF-I) metabolisms is not well understood. Clinical studies on GH secretion in CRF have yielded conflicting results. In vitro, pituitary GH secretion has been shown to be unimpaired in moderate uremia. CRF reduces binding of GH to liver as a result of decreased number of GH receptors. CRF induces elevation of serum GH concentrations and does not modify the circulating values of IGF-I. However, the somatomedin bioactivity of uremic serum is depressed, and unsaturated low-molecular-weight IGF-I-binding proteins have been suggested to act as inhibitory factors of IGF-I action. Circulating GH and IGF-I do not necessarily reflect the state of GH and IGF-I in tissues, and further investigations on the effect of CRF on GH and IGF-I metabolisms at the growth plate level are clearly required.

Child↗
PubMed1990

Renal cell carcinoma in childhood.

Renal cell carcinoma is extremely infrequent in children. We report a case of renal cell carcinoma in a 13-year-old male. Presenting manifestations were loin pain, fever, and weight loss. A palpable abdominal mass was found. Imaging studies showed a solid mass into the right kidney. Nephrectomy was performed and pathological examination demonstrated characteristic findings of renal cell carcinoma. This report emphasizes that renal cell carcinoma should be included in the differential diagnosis of renal masses in children.

Adolescent↗
PubMed1988

Unusual evolution of Wilms tumor in a patient with Wiedemann-Beckwith syndrome.

A very unusual case of Wilms tumor in a child with Wiedemann-Beckwith syndrome is presented. The patient had his first metastasis after a disease-free interval longer than three years. Later, he developed spinal epidural involvement. Both data emphasize the oncogenic potential of Wiedemann-Beckwith syndrome in children and support the contention that Wiedemann-Beckwith syndrome worsens the prognosis of Wilms tumor. Patients with Wilms tumor associated to Wiedemann-Beckwith syndrome should receive intensive therapy as well as close and prolonged follow-up in spite of apparent tumor remission.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1987

Idiopathic hypercalciuria in children: pathophysiologic considerations of renal and absorptive subtypes.

Sixteen children with idiopathic hypercalciuria and seven control children were observed. Patients were classified into two groups by means of an orally administered calcium loading test. Individuals with renal hypercalciuria (five children) had a high fasting urinary calcium/creatinine concentration ratio (0.27 +/- 0.05), a mild increase of this value after calcium administration (0.29 +/- 0.07, P less than 0.05), and elevated mean serum parathyroid hormone (PTH) concentrations (0.95 +/- 1.14 ng/ml). Patients with absorptive hypercalciuria (11 children) had fasting urinary calcium/creatinine concentration ratio of 0.11 +/- 0.04, a large increase of this index after calcium loading (0.25 +/- 0.06, P less than 0.0005), and normal levels of serum PTH (0.29 +/- 0.10 ng/ml). Next, we examined the effects of two different calcium intakes on urinary calcium excretion, serum calcium, PTH, and 1,25-dihydroxyvitamin D3 concentrations. In patients with absorptive hypercalciuria, the increased calcium intake resulted in significant increments of calciuria (P less than 0.0005), mild elevation of serum calcium concentration (P less than 0.05), and reduction of serum 1,25-dihydroxyvitamin D3 concentrations (P less than 0.005). By contrast, these values were not modified in children with renal hypercalciuria. Serum PTH did not change within each group. After dietary calcium supplementation, serum ratios of 1,25-dihydroxyvitamin D3 to calcium, phosphate, and PTH concentrations decreased significantly only in the group of children with absorptive hypercalciuria. Our data support the contention that 1,25-dihydroxyvitamin D3 metabolism is different in the two groups of patients with hypercalciuria.

Absorption↗
PubMed1987

Primary bronchopulmonary malignant melanoma. Case report.

A case of pulmonary melanoma is presented. Because of the tumor's evolution and clinical features and, in particular, its pathoanatomic characteristics, we believe that it complied with sufficient criteria for classification as primary bronchopulmonary malignant melanoma. The literature is briefly reviewed.

Bronchial Neoplasms↗
PubMed1987

Aluminum deposition in the central nervous system. Preferential accumulation in the hippocampus in weanling rats.

Simultaneous administration of 1,25-dihydroxyvitamin-D3, citrate, and aluminum-containing phosphate binders is frequently used in patients with chronic renal failure. In order to investigate whether citrate may represent a risk factor of aluminum intoxication, 16 Sprague-Dawley weanling rats were randomly assigned to four groups: 1,25-dihydroxyvitamin-D3 at 16 ng/kg/day was given to all groups except the control; in addition, two groups received either aluminum hydroxide at 160 mg elemental aluminum/kg/day, or aluminum citrate at 160 mg elemental aluminum/kg/day, respectively. The control group received only the vehicle. Extremely high aluminum concentrations were detected in the hippocampus of rats receiving aluminum compounds. This content of aluminum (microgram/g dry weight) was far higher than that found in other brain areas of the same animals (146.40 +/- 51.23 versus 4.49 +/- 0.62, P less than 0.001) as well as that detected in the hippocampus of the control animals (2.73 +/- 0.40). Thus, in non-uremic, weanling rats supplemented with 1,25-dihydroxyvitamin-D3, the administration of aluminum favors selective accumulation in the hippocampus. No differences between aluminum hydroxide and aluminum citrate administration were observed.

Aluminum↗
PubMed1986

Hypercalciuria associated with long-term administration of calcitriol (1,25-dihydroxyvitamin D3). Action of hydrochlorothiazide.

Urine calcium excretion was evaluated in 19 patients before and after calcitriol (1,25-dihydroxyvitamin D3) treatment that was followed up for a five- to seven-year period. The effects of increases of calcitriol dosage and modifications of calciuria with hydrochlorothiazide were systematically examined. The urine calcium excretion before calcitriol therapy was 2.3 +/- 0.8 mg/kg/day (mean- +/- SEM) and the urine calcium-creatinine concentration ratio was 0.12 +/- 0.04. With the dose of calcitriol at 23 ng/kg/day, these values increased to 3.2 +/- 0.8 mg/kg/day and 0.19 +/- 0.04, respectively. Following double dose of calcitriol (44 ng/kg/day), increments in calciuria and urinary calcium/creatinine concentration of 1.4 +/- 0.6 mg/kg/day and 0.10 +/- 0.03, respectively, were observed. With concomitant administration of hydrochlorothiazide (1 to 2 mg/kg/day) therapy at maintenance dose and calcitriol (31 ng/kg/day), the urine calcium excretion effectively decreased by 1.3 +/- 0.6 mg/kg/day and the urine calcium-creatinine concentration ratio by 0.05 +/- 0.02. The results suggest that children with calcium-phosphate disorders who require long-term treatment with calcitriol must be carefully monitored in terms of urine calcium excretion, especially when the dosages are increased to achieve maximal therapeutic efficacy. Calciuria induced by calcitriol administration is effectively reversed by addition of hydrochlorothiazide to the treatment regimen.

Adolescent↗
PubMed1986

Renal tubular acidosis in children. Diagnosis, treatment and prognosis.

To delineate the spectrum of clinical expressions of distal, type 1 renal tubular acidosis in children and to update progress in diagnosis, therapy, and prognosis, the medical records of 14 girls and 10 boys, seen over a 7 year period, who met the following criteria, were examined: persistent urinary pH more than 6, net acid excretion less than 70 microEq/min/1.73 m2, simultaneous serum total CO2 less than 17.5 mEq/1, and normal or mild impairment of the glomerular filtration rate. The mean age at diagnosis was 8 months. The presenting signs and symptoms were failure to thrive (50%), vomiting and/or diarrhea (37.5%), dehydration (12.5%), and poor feeding (8.3%). Mean values +/- SD of serum calcium (9.8 +/- 0.8 mg/dl), inorganic phosphate (5.6 +/- 0.8 mg/dl), and alkaline phosphatase (222.6 +/- 96.1 U/l) were normal. Hyperkalemia (serum potassium above 5.0 mEq/l) was present at diagnosis in 13 children. Type 4 renal tubular acidosis was ruled out by the inability to achieve a minimum urine pH. With a mean follow-up period of 28.1 +/- 25.3 months, after alkali therapy at 3.3-3.5 mEq/kg/day had been administered for at least 12 months, the growth parameters improved as follows: the percentile weight (mean +/- SD) increased from the initial 11.8 +/- 7.5 to the final 27.6 +/- 31.3 (p less than 0.003), and the length/height percentile increased from 11.5 +/- 7.3 to 29.7 +/- 24.2 (p less than 0.03). The relationship between urine calcium/creatinine ratio and serum total CO2 showed poor correlation.(ABSTRACT TRUNCATED AT 250 WORDS)

Acidosis, Renal Tubular↗
PubMed1985

[Schönlein-Henoch syndrome: review of a series of 142 cases].

Clinical and laboratory findings in 142 children with Schönlein-Henoch syndrome are studied. The children were diagnosed during a ten-year period (1974-1984). Purpura, as more significant clinical finding, was observed in all patients, followed by articular signs (61.2%), abdominal complaints (57.7%), renal signs (30.2%) and testicular (4.2%). IgA, IgG, IgM, complement and cryoglobulin alterations, are remarkable factors to assume an immunologic origin for the syndrome.

Child↗