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Biomedical subjects

A Clerico

Publications and source records attributed to A Clerico.

At least 109 records · Page 6Linked to original sources
PubMed1989

Specific binding of cardiac glycoside drugs and endogenous digitalis-like substances to particulate membrane fractions from human placenta.

We studied the characteristics of binding of cardiac glycosides to particulate membrane fractions from human placenta, to demonstrate that placental tissue is a suitable source of receptors for digitalis drugs. Moreover, we performed preliminary experiments with 125I-labeled digoxin and placental particulates to develop a radioreceptor assay for measurement of endogenous substances with activity similar to cardiac glycoside drugs (EDLS). Placental membrane fractions were incubated with [3H]ouabain (10 nmol/L) or 125I-labeled digoxin (50 pmol/L). With both ligands, binding followed a pseudo-first-order reaction kinetics and was saturable. Scatchard analysis revealed a single class of sites [for ouabain, KD = 20.2 +/- 5.8 nmol/L (mean +/- SEM), Bmax = 3.1 +/- 0.9 nmol per gram of protein; for digoxin, KD = 29.7 +/- 1.9 nmol/L, Bmax = 24.3 +/- 1.1 nmol per gram of protein]. As expected, digoxin was less potent than ouabain in displacing both tracers from digitalis drugs receptors; progesterone, cortisone, digitoxose, furosemide, bumetanide, and propranolol had no or little effect. Specific 125I-labeled digoxin binding was competitively inhibited by plasma and (or) urine extracts from newborns, adults, pregnant women, and patients with renal insufficiency. Inhibition of binding and volume of plasma and urine assayed were linearly related. These findings support the hypothesis that cardiac glycosides and EDLS can interact with the human placenta and suggest placental tissue to be a suitable source of receptors for cardiac glycosides.

Binding Sites↗
PubMed1988

Urinary albumin excretion in normal subjects and in diabetic patients measured by a radioimmunoassay: methodological and clinical aspects.

We have developed a radioimmunoassay method (RIA) to measure urinary albumin excretion. We determined the albumin excretion rate (AER) (micrograms/min) of 122 healthy subjects and 145 diabetic patients (115 type I, 30 type II). The results indicate that the RIA is sensitive (0.39 +/- 0.08 mg/L), precise (CV 5-8%), and gives reliable results on previously frozen urine samples. The distribution of the AER values in healthy subjects and diabetic patients was not normal. It was normalized by log or square-root transformation of the data. Seventy-three percent of diabetic patients lay within the normal range (0.6-10.6 micrograms/min). Twenty percent could be considered "at risk" to develop overt diabetic nephropathy because their albuminuria exceeded a threshold level of 15 micrograms/min chosen previously as the cutoff value for microalbuminuria. We found no correlation between AER and glycated hemoglobin, and only a weak correlation between AER and diabetes duration in type I diabetic patients.

Adolescent↗
PubMed1988

Increased urinary excretion of digoxin-like immunoreactive substance by insulin-dependent diabetic patients: a linkage with hypertension?

Excretion of digoxin-like immunoreactivity (DLIS) was measured by RIA in timed overnight urine collections from 91 normotensive nondiabetic subjects and 104 normotensive insulin-dependent diabetic (IDDM) patients. The mean +/- SD DLIS excretion rate for the diabetic patients significantly exceeded that for the controls (73 +/- 41 vs 63 +/- 36 pg/min, P = 0.024). In both groups, the mean DLIS excretion rates for men were significantly higher (P = 0.0014, P = 0.006) than for women. In the controls, the DLIS excretion rate significantly correlated with the urinary excretion rate of creatinine (P less than 0.01), Na+ (P less than 0.05), and K+(P less than 0.05), and with the subjects' body weight (P less than 0.01), body mass index (P less than 0.05), and systolic blood pressure (P less than 0.05). In the diabetics, the DLIS excretion rate was significantly correlated with body weight (P less than 0.05) and with urinary excretion rates for albumin (P less than 0.01), creatinine (P less than 0.01), Na+ (P less than 0.05), and K+(P less than 0.05). Our data indicate that: (a) increased amounts of a cardiac glycoside-like substance (or a group of substances) are excreted in the urine of IDDM patients; (b) the urinary excretion of DLIS seems to depend on glomerular filtration rate and physiocochemical properties of glomerular membrane, as well as on subjects' body mass; and (c) because cardiac glycoside-like substances may increase peripheral vascular resistance, increased urinary excretion of DLIS by IDDM patients may indicate a tendency to develop hypertension.

Adult↗
PubMed1988

Albuminuria estimated from proteinuria in diabetics. Is it a real alternative in clinical practice?

While proteinuria detectable by dip-sticks is the hallmark of overt diabetic nephropathy, urinary albumin excretion (UAE) above normal but Albustix-negative (so-called microalbuminuria) is the main characteristic of the preproteinuric phase of the diabetic renal disease. Reliable measurement of UAE requires very sensitive and accurate methods, such as radioimmunoassay (RIA), which, however, are not suitable for routine UAE analysis. The Coomassie Brilliant Blue dye binding method has been suggested to be a simple and economical way of indirectly measuring albuminuria in diabetic patients. In the present paper, we compared the chemico-clinical characteristics of a RIA method with those of the Coomassie dye binding method, in order to verify if it is really possible to calculate albuminuria from proteinuria (and vice versa) by a simple linear regression equation, as previously suggested. The RIA has shown a better sensitivity and accuracy in comparison to the dye binding method. Our study suggests that there is not a linear relationship between proteinuria and albuminuria in diabetic patients. Indeed, the ratio between the total proteinuria, as measured with the dye method, and the albuminuria, as measured by a specific and sensitive RIA, varies greatly in diabetic patients with or without glomerular nephropathy. While the dye binding method appears the best procedure for the assay of total microproteinuria, since it is precise, cheap and feasible, the RIA, due to its high sensitivity and specificity, is more suitable for early and accurate detection of microalbuminuria, as well for the close follow-up of subjects at risk of developing overt diabetic nephropathy.

Albuminuria↗
PubMed1988

Endogenous cardiac glycoside-like substances in newborns, adults, pregnant women and patients with hypertension or renal insufficiency.

In an attempt to confirm the presence of endogenous substances with cardiac glycoside-like activity, the biological and immunological cardiac glycoside-like activity was measured by a sensitive solid-phase radioimmunological assay (RIA), two radioreceptor assays (RRA), and a 86Rb uptake method in normal subjects and in some pathophysiological conditions characterized by sodium retention and volume expansion. Significant concentrations of digoxin-like immunoreactive substances (DLIS) were measured in plasma (or serum) of normal subjects while significantly higher levels were found in pregnant women, newborns and in patients with renal impairment, and in some with essential hypertension. Concentrations in urine of normal adults or newborns were several times higher than in plasma. The results obtained by RIA correlated with those obtained by RRA and 86Rb uptake methods. In 88 normal subjects, DLIS excretion rates (overnight urine collection) in men were significantly higher than in women (68.6 +/- 23.6 pg/min vs 50.9 +/- 21.0 pg/min, p less than 0.01). The DLIS excretion rates correlated with creatinine, Na and K urinary excretion rates, and also with the subjects' body weight, height, body mass index, and systolic blood pressure. These findings confirm the presence of endogenous substances with immunological and biological activity similar to cardiac glycosides in human body fluids and also confirm the hypothesis that these endogenous factors may be involved in fluid and electrolyte regulation in man. In addition, the present data indicate that urinary excretion of DLIS is dependent on body mass and renal glomerular filtration.

Adult↗
PubMed1988

Excretion of digoxin-like immunoreactivity in urine of normal subjects: correlations with excretion of creatinine and electrolytes.

To verify whether there is a variation in the 24-h urinary excretion of digoxin-like immunoreactivity (DLIS) in humans, we studied 18 normal adults, who collected their urines for 24-h in several portions. We then measured DLIS (by means of a sensitive RIA method), creatinine, sodium, and potassium concentrations in the urine samples. The mean urinary excretion rate for DLIS in the complete 24-h collection was 84.8 (SD 31.3) pg/min. The mean DLIS urinary excretion rate calculated for overnight collections was significantly lower than those of afternoon collections (P less than 0.01) and the 24-h collection (P less than 0.05). Significant positive correlations were found between urinary DLIS and excretion rates for creatinine (r = 0.347, P = 0.0016), Na+ (r = 0.232, P = 0.038), and K+ (r = 0.323, P = 0.003), respectively. Our data suggest that urinary excretion of DLIS is higher during "active" hours of the day, especially in the afternoon, than at rest, during the night.

Adult↗
PubMed1987

Bilateral rhabdomyomatous tumor relapsed as typical triphasic Wilms' tumor.

The authors report on a child affected with bilateral renal tumor, which was treated with cancer chemotherapy before and after surgery. Twenty-eight months after the discontinuance of therapy, a neoplasm was disclosed in the left kidney and then removed. Histologically, the bilateral tumor excised by the first surgery could be classified as biphasic Wilms' tumor, rhabdomyomatous variant, whereas the neoplasm removed by the second surgery was the typical triphasic Wilms' tumor. The authors suggest that preoperative chemotherapy might have played a role in the histologic changes of the initial tumor. Nonetheless, it is also tempting to postulate that the two histologic variants of Wilms' tumor could have occurred in the patient in spite of any treatment.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1987

Nonfamilial intestinal polyposis and brain tumor in a 5-year-old girl.

A 5-year-old girl with glioblastoma multiforme and simultaneous adenocarcinoma in one of multiple colonic polyps is the youngest reported case of Turcot's syndrome. A literature survey and a classification based on family pedigree and pattern of inheritance are proposed.

Adenocarcinoma↗