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Biomedical subjects

J Coello

Publications and source records attributed to J Coello.

25 records · Page 2Linked to original sources
PubMed1993

Spectrophotometric analysis of a pharmaceutical preparation by principal component regression.

The use of a principal component regression procedure for quantitative analytical control of pharmaceutical preparations was investigated. The procedure was applied to the simultaneous quantitation of the active compound and preservative of a syrup by resolving their respective UV spectra. The most suitable conditions for quantitation were established and the results were compared with those obtained by HPLC.

Benzamides↗
PubMed1988

Atrial natriuretic factor increases after a protein meal in man.

1. The renal function changes induced by dietary protein are thought to result from the activity of hormonal factors that remain as yet undefined. Since a meat meal and high dose atrial natriuretic factor (ANF) infusions have similar effects on glomerular filtration rate, natriuresis and kaliuresis, we decided to investigate the possibility that a protein meal could stimulate ANF activity. 2. We studied 10 normal volunteers who had a fixed protein and sodium intake for 7 days before the experiments. The subjects received a meat meal (1-1.5 g of protein/kg) and, on a separate occasion, a carbohydrate meal that had a similar caloric, sodium and potassium content. Diuresis was stimulated with water ingestion, and urine collections were obtained before the meals (baseline) and after the meals for a period of 3 h. Blood samples were obtained 30 min and 5 min before the meals and every hour for 3 h in the period after the meal. 3. The protein meal, but not the carbohydrate meal, was associated with parallel increments in plasma immunoreactive ANF (i-ANF), natriuresis, kaliuresis and glomerular filtration rate (estimated from creatinine clearances) which reached peak values 2-3 h after the meal. The mean increment of plasma i-ANF after the protein meal represented a twofold increase over baseline levels. 4. We conclude that ANF may participate in the physiological response to an oral protein load.

Atrial Natriuretic Factor↗
PubMed1988

Urinary prostaglandin E and kallikrein activity in glomerular hyperfiltration induced by a meat meal in man.

Because renal vasodilator systems may be involved in the physiologic response to a protein meal, we studied the relationship of prostaglandin E (PGE) and kallikrein (KE) activity to the renal hemodynamic changes induced by a meat meal. Ten normal subjects on a maintenance diet providing 1 g protein per kg and 100 mmol Na daily were studied before and after a meal of 86 g of meat protein, once without medication, and again after treatment with indomethacin (150 mg daily for 3 days before and 50 mg the morning of the test). A carbohydrate meal of similar caloric, Na and K content was used in control studies. Glomerular filtration rate (GFR, inulin clearance), renal blood flow (RBF, para-aminohippurate [PAH] clearance), PGE and kallikrein urinary excretion were determined. All studies were performed during water diuresis to avoid bladder catheterization. The protein load induced an increase in GFR (ml/min, mean +/- s.e.m.: baseline 107.2 +/- 6.05, peak postmeal 146.4 +/- 6.79, p less than 0.01) and RBF (baseline 529.7 +/- 42.9, postmeal 678.9 +/- 61.9, p less than 0.05). Renal hemodynamic changes were unrelated to changes in urinary PGE and KE excretion. Indomethacin treatment inhibited PGE excretion by 73% during the test meal but did not modify the protein-induced hyperfiltration. Our results suggest that these renal vasodilator systems are not primarily responsible for the hyperfiltration response. In addition, the data show that inhibition of prostaglandin synthesis is not a practical approach to prevent glomerular hyperfiltration in clinical practice.

Adult↗
PubMed1985

Neuraminidase production by streptococci from patients with glomerulonephritis.

Autoantigenic events in acute poststreptococcal glomerulonephritis (APSGN) may result from neuraminidase-induced alterations in immunoglobulin levels. Whether streptococci from patients with APSGN produced neuraminidase and, if so, what substrates could be used for screening purposes and what were of potential clinical relevance were determined. Group A streptococci cultured from 20 patients with APSGN and four patients with acute rheumatic fever and group B, C, D, and G streptococci cultured from other individuals were reacted with the substrates to determine neuraminidase activity by the thiobarbituric acid assay. Neuraminidase production was detected in 16 of 20 streptococci from patients with APSGN. Partial purification by Sephadex G-150 chromatography gave two peaks, and polyacrylamide gel electrophoresis gave two bands with neuraminidase activity. Bovine mucin was the most useful substrate to detect neuraminidase production by nephritogenic streptococci, and with respect to human substrates, IgM was the most sensitive and renal basement membrane the least sensitive to enzyme action.

Glomerulonephritis↗
PubMed1981

Neuraminidase activity and free sialic acid levels in the serum of patients with acute poststreptococcal glomerulonephritis.

It has been suggested that in acute poststreptococcal glomerulonephritis, streptococcal neuraminidase may remove sialic acid from some normal plasma or tissue components, thus rendering it antigenic. We therefore investigated serum neuraminidase activity and serum and urinary free neuraminic acid levels, using the thiobarbituric acid method, in 39 patients with acute poststreptococcal nephritis. Serum neuraminidase activity was found in eight patients, and increased thiobarbituric acid-reactive material (presumed to be free neuraminic acid on the basis of absorption-spectrum similarity) was found in 28 patients. Serial determinations in 21 patients indicated that neuraminidase activity was present only initially and that free neuraminic acid levels decreased with time, usually becoming undetectable after four weeks. Determinations in patients with other renal and nonrenal diseases suggested that the findings were characteristic of poststreptococcal nephritis. Urinary neuraminic acid levels were unrelated to serum levels and were not markedly different between patients and normal subjects. These data suggest a role for neuraminidase activity in acute poststreptococcal nephritis, but they do not indicate whether it is primary or secondary.

Acute Disease↗