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Biomedical subjects

M G Del Chicca

Publications and source records attributed to M G Del Chicca.

At least 37 records · Page 2Linked to original sources

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↗

Correlations between digoxin-like immunoreactivity and electrolyte values in urinary samples of newborns.

Elevated levels of a group of substances with digoxin-like immunoreactivity (DLIS) are present in biological fluids of newborns. These endogenous substances could also have the biological properties of cardiac glycosides, such as natriuretic and vasoconstrictor activity. Therefore, DLIS could be involved in electrolyte and volume regulation in infants. We measured DLIS, electrolyte (Na+, K+, Cl-) and creatinine concentrations in 157 urine samples collected from full-term and preterm infants, with the aim to establish if a correlation exists between the urinary DLIS levels and the respective values of these electrolytes. Significant and positive correlations were found between the urinary concentrations of DLIS and electrolytes. In addition, electrolyte values correlated significantly between themselves. DLIS, K+ and Cl- values correlated positively with urinary creatinine concentrations (n = 142). A significant multiple correlation was found among DLIS concentrations and creatinine and Cl- values. We also studied the DLIS concentrations in serum samples collected at birth in peripheral blood of the mothers and in umbilical cord and gastric aspirate of 5 full-term infants. We observed that DLIS values in newborns are significantly higher than the respective values of the mothers. In conclusion, our data do not demonstrate a clear relationship between DLIS and electrolyte concentrations in urine samples of newborns. Further investigations are necessary to elucidate the biochemical and physiological properties of DLIS.

Adolescent↗

Acute hypotensive effect of calcium antagonists and endogenous digitalis-like immunoreactivity in human essential hypertension.

Evidence has been provided on the increased presence, in essential hypertension, of endogenous digitalis-like factor(s) [DLIS, digoxin-like immunoreactive substance(s)] able to cross-react with antidigoxin antibodies and to inhibit the membrane-bound sodium-potassium pump. An inhibition of the sodium pump could lead, in smooth muscle cells, to an increase of intracellular calcium ions and to an increase of total peripheral resistances. In this study the relation between plasma levels of DLIS and the acute hypotensive effect of a calcium antagonist (nifedipine) has been evaluated in a group of borderline to severe hypertensive patients and in a control group of normotensive subjects. The results obtained confirm that the hypotensive effect of nifedipine is related to pretreatment blood pressure and show, only in hypertensive patients, a significant relation of DLIS with both pretreatment blood pressure and blood pressure decrement induced by nifedipine. These findings are compatible with a possible role of DLIS in modulating cellular calcium handling.

Adult↗

Modifications in the concentrations of circulating myoglobin after treatment with low doses of adriamycin.

The modifications in the concentration of circulating myoglobin have been studied by means of a radioimmunoassay in 15 cancer patients undergoing polychemotherapy including adriamycin. In 8 patients significant increases in myoglobin levels were found after injection of low doses of the drug (25-50 mg/m2). Moreover, a disturbance of the normal biorhythm of the protein was evident in 12 patients. Creatine kinase-MB was evaluated by means of a radioimmunoassay, but there was no relation between an increase in the isoenzyme and an increase in myoglobin. No ECG modifications were detected. These data indicate that the measurement of myoglobin may offer an indication of myocardial or skeletal muscle damage caused by adriamycin.

Adult↗

Macro serum CK-BB in a woman with severe primary hypothyroidism.

We report the case of a woman with severe hypothyroidism and without concomitant myocardial damage, in whom elevated CK-MB values were measured by radioimmunological and enzymatic methods before and after thyroid replacement therapy. The patient's CK-MB activity was shown to be actually due to an atypical CK band between CK-MM and CK-MB (also termed "macro CK" or "idiopathic serum CK-BB").

Aged↗

Evaluation of a new radioimmunological assay for the determination of the B subunit of creatine kinase enzyme.

We used a new radioimmunological (RIA) kit for the assay of B subunit of creatine kinase enzyme (CK). This RIA system uses a specific antisera against the B subunit as ligant, human CK-BB labelled with 125I as tracer, and purified human CK-BB isoenzyme as standard. The mean (+/- SD) sensitivity obtained was 0.25 +/- 0.16 ng/tube and the between assay variability was about 9-10%. Serum levels of 113 normal subjects was not normally distributed. The 95% of values was found below 5 ng/ml. This new RIA is usefull in clinical practice when serum levels of CK-BB isoenzyme must be determined. This method is quickly and it is characterized by a good degree of precision, but the CK-MB isoenzyme cross-reacts for about 40% in this RIA system. Therefore, for the clinical diagnosis by means of this RIA it is necessary to rule out the concomitant elevations of serum CK-MB values.

Creatine Kinase↗

Apparent free cortisol concentrations in patients with anorexia nervosa at different stages of the disease.

We have measured the total cortisol concentration (TC) and the apparent free cortisol concentration (AFCC) in plasma samples of 17 patients with anorexia nervosa (AN) at different stages of the disease, in basal conditions and after suppression test. We measured free cortisol values directly by a RIA method in dialyzed plasma samples after an equilibrium dialysis system. We have found significantly elevated TC and AFCC values in basal conditions and after suppression test only in the group of patients in the severe stage of the disease. In addition, a significant (p less than 0.05) correlation existed between percent loss of ideal body weight TC and AFCC values after suppression test. Our results suggest that the hypothalamus-pituitary-adrenal axis may be grossly impaired only in the severe stage of AN.

Adolescent↗

Detection of hypothyroid myopathy by measurement of various serum muscle markers--myoglobin, creatine kinase, lactate dehydrogenase and their isoenzymes. Correlations with thyroid hormone levels (free and total) and clinical usefulness.

An accurate and close follow-up of serum levels of thyroid hormones and various muscle markers (myoglobin, creatine kinase and its isoenzymes CK-MB and CK-BB, lactic dehydrogenase, alpha-hydroxybutyric dehydrogenase, etc.) was carried out in 10 hypothyroid patients on replacement therapy. The main muscle markers, creatine kinase and myoglobin, were elevated respectively in 9 and 6 subjects. In 1 male significant CK-MB traces were measured, while in 1 woman significant CK-BB amounts were assayed. Significant correlations between patients' thyroid hormones and the levels of the muscle parameters were found. The rate of normalization of thyroid hormones and muscle markers in relation to replacement therapy was also studied. Myoglobin and creatine kinase have proved to be the best indicators of the hypothyroid myopathy, since they are sensitive for the early detection of muscle involvement due to the metabolic disorder and are closely correlated to the metabolic conditions of patients.

Adolescent↗

Elevated free cortisol plasma levels in patients with prostatic carcinoma undergoing treatment with estrogens.

The total cortisol concentration (TCC), the percentage of free cortisol (%FC) and the apparent free plasma cortisol concentration (AFCC) have been determined in plasma samples of 9 patients affected by prostatic carcinoma undergoing treatment with estrogens measured by an equilibrium dialysis system and a radioimmunological method. The values found in this group of patients were compared to those obtained in 9 untreated control patients and in normal healthy persons. The mean TCC values found in treated patients were significantly higher than in the controls, both in basal condition (circadian rhythm) and after dynamic tests, while the mean %FC values were significantly lower than the controls except for the results obtained after an ACTH stimulation test. The mean AFCC values in treated patients were elevated both in basal condition and after the dexamethasone suppression test (DST), but the difference between the two groups of patients was statistically significant only after DST. This study demonstrates that patients with prostatic carcinoma undergoing treatment with estrogens can have markedly increased free plasma cortisol levels with an impairment of the hypothalamus-pituitary-adrenal axis.

Adrenocorticotropic Hormone↗

Circadian variations of serum myoglobin levels in normal subjects and patients with polymyositis.

Circadian variations in myoglobin levels were determined in 18 normal volunteers and in 10 patients with active polymyositis. In all the controls and in 9 of the 10 patients, serum myoglobin concentrations were highest at 9 am, fell significantly during the day to reach a nadir between 6 and 12 pm, remained constant until midnight, and then rose again at 3 am. The percent differences between the highest and lowest values ranged from 21-66%. This pattern was observed in both untreated patients and patients receiving 6-methyl-prednisolone, which was given either in a single dose at 8 am or in divided doses (8 am and 8 pm). These data demonstrate that the time of sample collection must be taken into account when myoglobin levels are used as a marker of muscle damage.

Adult↗

Free-cortisol assay by immunoextraction: comparison with an equilibrium dialysis procedure.

We describe a new method for directly determining the apparent free cortisol concentration in plasma samples by use of an antibody-coated test-tube RIA. Buffer-diluted plasma or standard serum is added to antibody-coated test tubes, incubated at 4 degrees C for 4 h, and the solutions are aspirated. 125I-labeled cortisol is added to each tube and incubated for 3 h at 4 degrees C. Then the insides of the tubes are washed and their radioactivities counted. The standard curve is in terms of free cortisol, the standard serum solutions having been measured with an equilibrium dialysis procedure. Plasma samples (n = 155) from normal subjects and from various patients, measured with the new immunoextraction method and the equilibrium dialysis technique, gave results that correlated well (r = 0.847, p less than 0.001). Results by this direct RIA also correlate well with the clinical adrenocortical status of patients for whom data on total plasma cortisol may be misleading. This simple, easy RIA is suited to be the routine method for free cortisol in plasma.

Anorexia Nervosa↗