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Biomedical subjects

S de Castro

Publications and source records attributed to S de Castro.

At least 19 recordsLinked to original sources
PubMed1995

Iron metabolism and fungal infections in patients with haematological malignancies.

AIM: To determine whether iron metabolism influences the incidence of systemic fungal infection in patients with haematological malignancies. METHODS: The study population comprised 74 patients who had undergone myeloablative chemotherapy. Systemic fungal infections were classified as confirmed (histological confirmation or characteristic septate hyphae) or possible (antibiotic resistant fever which resolved following administration of intravenous amphotericin B, together with either typical radiographic lesions or massive oropharyngeal candidiasis). Parameters of iron metabolism included serum iron concentrations, total iron binding capacity, serum transferrin, and ferritin concentrations and transferrin saturation values. RESULTS: Patients who developed a fungal infection had substantially increased transferrin saturation values and ferritin concentrations at diagnosis together with low serum transferrin and high serum iron concentrations. This profile was present in patients with a fungal infection regardless of the underlying haematological disorder. CONCLUSION: Increased transferrin saturation values and high ferritin concentrations may be additional risk factors for the development of systemic fungal infection in patients with haematological malignancies.

Acute Disease↗
PubMed1993

Comparison of two techniques (flow cytometry and alkaline immunophosphatase) in the evaluation of alveolar macrophage immunophenotype.

The alveolar macrophage (AM) plays an essential role in the pathogenesis of interstitial lung diseases. The expression of specific membrane antigens is related to the functional or madurative status of the cells of mononuclear phagocyte system. The aim of this study was to analyze the expression of several markers (HLA-DR, CD11b, CD16, CD14) in AM obtained by bronchoalveolar lavage from control patients (n = 6), patients with sarcoidosis (n = 6), diffuse neoplastic infiltration of the lung (n = 7), pulmonary fibrosis (n = 4), and hypersensitivity pneumonitis (n = 3) by two evaluation techniques (flow cytometry and alkaline immunophosphatase). In the light of the results we can conclude that in the immunophenotypical study of the alveolar macrophage, flow cytometry (with semiquantitative evaluation to avoid the problem of autofluorescence) is a useful tool in the evaluation of those antigens that are only weakly or moderately expressed on AM (CD11b or CD14), whereas the alkaline immunophosphatase technique is of great interest in the evaluation of those that are strongly expressed (i.e., HLA DR). Additionally, the variable expression of the different antigens in the different alveolar-interstitial pathological states is patent in some diseases.

Alkaline Phosphatase↗
PubMed1993

Effect of transferrin concentration on bacterial growth in human ascitic fluid from cirrhotic and neoplastic patients.

Cirrhotic patients with ascites have an unusually high frequency of development of spontaneous bacterial peritonitis. Iron availability is a key factor in bacterial growth and the ability of the host to limit it is associated with resistance to infection. The present study was undertaken to evaluate the influence of iron and transferrin on bacterial growth in ascitic fluid from 25 biopsy-proven cirrhotic and nine neoplastic carcinomatous patients. No significant differences were found when comparing total ascitic fluid iron between the two groups but ascitic fluid transferrin concentration was significantly lower in cirrhotic (29.26 mg dl-1 SD 29.58) than neoplastic (96.57 mg dl-1 SD 76.01) patients. Moreover, a significant negative correlation was found between bacterial growth and transferrin concentration in ascitic fluid (P = 0.039). When the iron concentration in ascitic fluid was experimentally elevated (50 micrograms dl-1 or 150 micrograms dl-1) we observed a progressive increase in bacterial growth. If transferrin concentration is simultaneously elevated (250 mg dl-1) this increase does not occur. These findings indicate that the transferrin level is an important factor in the regulation of bacterial growth in ascitic fluid and that the low concentration found in cirrhotic patients could facilitate spontaneous bacterial peritonitis.

Adult↗
PubMed1991

Hormonal regulation of potassium shifts during graded exhausting exercise.

Serum potassium, aldosterone and insulin, and plasma adrenaline, noradrenaline and cyclic adenosine 3':5'-monophosphate (cAMP) concentrations were measured during graded exhausting exercise and during the following 30 min recovery period in six untrained young men. During exercise there was an increase in concentration of serum potassium (4.74 mmol.l-1, SEM 0.12 at the end of exercise vs 3.80 mmol.l-1, SEM 0.05 basal, P less than 0.001), plasma adrenaline (2.14 nmol.l-1, SEM 0.05 at the end of exercise vs 0.30 nmol.l-1, SEM 0.02 basal, P less than 0.001), plasma noradrenaline (1.10 nmol.l-1, SEM 0.64 at the end of exercise vs 1.50 nmol.l-1, SEM 0.05 basal, P less than 0.001), serum aldosterone (0.92 nmol.l-1, SEM 0.14 at the end of exercise vs 0.36 nmol.l-1, SEM 0.05 basal, P less than 0.01), and plasma cAMP (35.4 nmol.l-1, SEM 2.3 at the end of exercise vs 21.4 nmol.l-1, SEM 4.5 basal, P less than 0.05). While concentrations of serum potassium, plasma adrenaline and cAMP returned to their basal levels immediately after exercise, those of plasma noradrenaline and serum aldosterone remained elevated 30 min later (1.90 nmol.l-1, SEM 0.01, P less than 0.01; and 0.85 nmol.l-1, SEM 0.12, P less than 0.01, respectively). Serum insulin concentration did not change during exercise (6.47 mlU.l-1, SEM 0.58 at the end of exercise vs 5.47 mlU.l-1, SEM 0.41 basal, NS) but increased significantly (P less than 0.02) at the end of the recovery period (7.12 mlU.l-1, SEM 0.65).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Vitamin B6 status in uremia.

We have studied vitamin B6 status in 26 uremic patients, 18 on maintenance hemodialysis and 8 nonhemodialyzed. The vitamin B6 status was estimated by an assay of erythrocyte aspartate aminotransferase and coenzyme stimulation. Hemodialyzed uremic patients were found to have vitamin B6 deficiency. Patients were treated with 150 mg pyridoxine hydrochloride daily for 4 weeks. Erythrocyte aspartate aminotransferase increased significantly in both groups of uremic patients, the increase being greater in hemodialyzed patients. In vitro pyridoxal phosphate stimulation produces an erythrocyte aspartate aminotransferase activity greater than that obtained before pyridoxine hydrochloride administration. After cessation of pyridoxine hydrochloride treatment, erythrocyte aspartate aminotransferase decreases in hemodialyzed patients, while it remains elevated in nonhemodialyzed patients. The data obtained appear to indicate that vitamin B6 administration to patients with chronic renal insufficiency must be appraised not only for correcting the deficit but also for increasing the intracellular pyridoxal phosphate concentration, which could modify the possible functional impairment at the level of apoenzymes that use pyridoxal phosphate.

Adult↗
PubMed1984

Spinal metastatic disease: analysis of factors determining functional prognosis and the choice of treatment.

The authors surveyed 31 surgical and radiotherapy series comprising over 2300 patients with spinal metastases to determine the influence of factors such as tumor biology and topography, pretreatment neurological status, the presence of a myelographic block, the progression rate of symptoms, and the general medical condition of the patient on both the functional prognosis and the choice of treatment. Both life expectancy and the functional results after therapy are mainly dependent on tumor biology, which in turn determines radiosensitivity. The remaining factors seem to have only complementary predictive power. Because radiotherapy has been found to be as effective as operation plus radiotherapy in the management of the majority of patients with spinal metastases, it is very important to improve the selection of surgical candidates (less than 42% of the total cases) to prevent unnecessary surgery-related morbidity and mortality. Factors considered important in the selection of therapy are the location of the tumor within the spinal canal, the neurological status at the time of treatment, and the systemic condition of the patient.

Combined Modality Therapy↗
PubMed1983

Serum glycosidases in diabetes mellitus in relation to the retinopathy and to the length of the disease.

The following glycosidase activities in sera have been studied: alpha-D-mannosidase, beta-D-glucuronidase, N-acetyl-beta-D-galactosaminidase, alpha-D-galactosidase, beta-D-galactosidase, alpha-D-glucosidase, beta-D-glucosidase and beta-D-fucosidase, in diabetic patients in relation to the presence of microangiopathy, evident by retinopathy, and to the length of the disease. A significant increase of all the enzyme activities, except for alpha-D-galactosidase was found. These elevations were independent of the development of retinopathy and the duration of the diabetic process.

Adolescent↗
PubMed1981

[Erythrocyte levels of ALA-dehydrase and uro-synthetase in chronic renal insufficiency (author's transl)].

Erythrocyte levels of ala-dehydrase and uro-synthetase as well as hematocrit, hemoglobin, iron levels and serum iron binding capacity were studied in a group of 28 patients with chronic renal failure in hemodialysis and compared to those of a control group. As is usual, hematocrit, hemoglobin an iron levels were significantly decreased, as were ala-dehydrase levels, while uro-synthetase levels were within normal levels. These results are interpreted as a blockade of the biosynthetic pathway of the protoporphyrins, which lends support to the hypothesis of an existing defect in hemoglobin synthesis in patients with chronic renal failure.

Ammonia-Lyases↗