Biomedical subjects
Publications and source records attributed to G Iacono.
Bowel frequency was recorded, on a diary sheet basis, in 662 children from six Italian cities. There is a wide interindividual variability, showing a sharp decrease with age; we report the distribution of the percentiles in the different age groups. Among infants, the breast-fed ones pass significantly more stools than the formula-fed.
We screened 569 children with acute onset diarrhoea from five Italian towns for heat stable enterotoxin produced by Escherichia coli. We compared an enzyme linked immunoabsorbent assay (ELISA) with the standard suckling mouse assay for detection of the enterotoxin. A total of 31 (5.4%) children were found who had strains of E coli that produced heat stable enterotoxin: 26 strains were positive in both tests, four only in the suckling mouse assay, and one only in the ELISA. Compared with the suckling mouse assay the sensitivity of the ELISA was 87% and the specificity was 99.8%. The mean age of the children with E coli that produced heat stable enterotoxin was 22 months. Fifteen (48%) of the children had ingested potentially contaminated food and five (17%) had a previous contact with someone with diarrhoea. The clinical picture was milder than that described in developing countries. Faecal osmolality and the osmolal gap were consistent with a secretory diarrhoea in 12 out of 15 (80%) of these children. The mean duration of the diarrhoea was five days. Heat stable enterotoxin produced by E coli is a common cause of mild diarrhoeal illness in Italian children.
The action of acetylcholine (ACh) on intracellular sodium activity (alpha iNa) was studied in sheep Purkinje fibers by means of a Na+-selective microelectrode technique while transmembrane potentials and contractile force were simultaneously recorded. In quiescent fibers, 10(-4) to 10(-5) M ACh shifted the resting potential to less negative values and increased alpha iNa from 5.57 +/- 0.21 to 6.45 +/- 0.35 mM (+15.8%, P less than 0.005). In other experiments, ACh induced a depolarization that initiated spontaneous activity. In fibers driven at 60 beats/min, ACh prolonged the action potential, increased alpha iNa from 7.98 +/- 0.15 to 9.36 +/- 0.3 mM (+17.29%, P less than 0.005), and increased contractile force. Norepinephrine (10(-5) to 10(-6) M) increased contractile force and decreased alpha iNa, but in its presence ACh still increased force and alpha iNa and vice versa. Strophanthidin (10(-4) M) increased alpha iNa, and 3 x 10(-6) M propranolol and 10(-6) M atropine decreased alpha iNa. Both strophanthidin and atropine (but not propranolol) prevented the increase in alpha iNa by ACh. It is concluded that the ACh increases alpha iNa and contractile force through the inhibition of the sodium pump and that these actions are due to the activation of the muscarinic receptor and not to endogenously released norepinephrine.
The mechanisms of induction of early reperfusion arrhythmias were studied in sheep cardiac Purkinje's fibers superfused in vitro. Transmembrane potentials, intracellular sodium activity (aiNa), and contractile force were recorded. Stoppage of the flow of Tyrode's solution (ischemia) for 1 hour initially decreased slightly aiNa (-0.57 mmol -7.2%), increased the action potential amplitude (+6.1%) and duration (+7.8%), and decreased diastolic depolarization slope (-45.2%). As the ischemia continued, aiNa increased progressively (to 12.53 mmol, +56.2%), whereas force peaked (+395%) after about 30 minutes and then began to decrease. By the end of ischemia, there was a decrease in action potential amplitude (-14.9%) and duration (-39.6%), whereas diastolic depolarization slope reincreased again almost to control value (-7%). When the flow of Tyrode's solution was resumed (reperfusion), force markedly increased (+211.1%) and oscillatory potentials initiated arrhythmias (extrasystoles and repetitive fast discharge) in 64% of tests. Force and aiNa decreased relatively rapidly. The arrhythmias initiated after 58.4 +/- 1.8 seconds of reperfusion and lasted 101.5 +/- 3.2 seconds. When [Na]o was increased by +19.2%, reperfusion arrhythmias occurred after only 30 minutes of ischemia. Thus, in Purkinje's fibers superfused in vitro, early reperfusion arrhythmias are induced by oscillatory potentials caused by calcium overload, which is enhanced by the increase in aiNa during ischemia.
The induction of spontaneous repetitive activity by a drive ('overdrive excitation') was studied in the sinoatrial node of the guinea pig by recording electrical and mechanical activity in sinoatrial preparations made quiescent by exposure to 20 mM caffeine of caffeine plus high [Ca]0. Electrical drive induced action potentials that were followed by oscillatory potentials and simultaneous aftercontractions. The oscillatory potentials (and the associated aftercontractions) increased in magnitude with successive action potentials, thereby initiating spontaneous beats during slow drives or after fast drives. The repetitive activity eventually slowed and ceased abruptly as the oscillatory potential failed to attain the threshold. Overdrive induced oscillatory potential and aftercontractions even when it did not initiate spontaneous activity. These results suggest that in the presence of caffeine calcium overload can occur in the sinoatrial node and result in oscillatory potentials and abnormal automaticity.
To evaluate the effectiveness of enteric-coated pancreatic enzyme supplements in comparison to conventional preparations of ingested enzyme on growth and nutritional parameters of patients with cystic fibrosis, we conducted a long-term study involving 40 patients. The data reproduced here were recorded after 6 months of therapy with powder-containing capsules or with enteric-coated products. Fat absorption was estimated by measurement of steatorrhoea with the steatocrit method. All parameters studied improved after enteric-coated pancreatic enzyme therapy, with a statistically significant increase in weight, cholesterol and haemoglobin values. Furthermore, the number of patients with positive steatocrit test was lower after therapy with enteric-coated enzyme supplementation. These findings suggest that the enteric-coated product not only reduces steatorrhoea, but above all improves the nutritional parameters and growth of patients affected by cystic fibrosis.
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To examine the role of sex steroid hormones in the development of autoimmune diseases, we studied five patients with Klinefelter's syndrome associated with autoimmune disease, three of whom had Sjögren's syndrome (SS) and two of whom had systemic lupus erythematosus (SLE). Serum testosterone (T) and LH levels, antinuclear antibodies (ANA) and rheumatoid factor (RF) titers, erythrocyte sedimentation rate (ESR), hemolytic complement (CH50) levels, and peripheral T lymphocyte subsets (OKT3+, OKT4+, and OKT8+) were measured before treatment, after 60 days of placebo treatment, and after 60 days of oral T undecanoate (TU) treatment. Before treatment and after placebo, with respect to normal men, the patients had lower serum T and higher LH levels, lower percentages and absolute values of OKT3+ (total T lymphocytes) and OKT8+ (suppressor/cytotoxic T lymphocytes) cells, and, consequently, an increased OKT4/OKT8 ratio. Hemolytic complement (CH50) in serum was below normal in the two patients with SLE, while it was normal in the patients with SS. The ESR was above normal in all patients, and all had high titers of ANA and RF. After TU therapy, serum T levels increased and LH levels decreased, but not to normal. OKT3+ and OKT8+ cells and the OKT4/OKT8 ratio became normal, and RF and ANA titers decreased. The CH50 level did not change in the SS patients, while it increased to normal in the two patients with SLE. The ESR decreased in all patients during therapy. Furthermore, after TU therapy, both the SS and SLE patients had a clinical remission of their autoimmune disease. Our results indicate a therapeutic effect of T on autoimmune diseases in patients with hypogonadism and Klinefelter's syndrome.
T-lymphocyte subpopulations, anti-thyroid microsomal antibody titres, and free triiodothyronine and free thyroxine levels were investigated in 10 patients with Graves' disease before, during and after pregnancy. Twenty pregnant subjects and 100 normal age-matched, non-pregnant female volunteers served as controls. Pregnant patients with Graves' disease showed decrease levels of free triiodothyronine and free thyroxine, and decreased titres of anti-thyroid microsomal antibodies, with clinical remission during the second and third trimesters of pregnancy. Post partum, 9 patients showed clinical relapse, and all showed a return of enhanced levels of free triiodothyronine, free thyroxine and anti-thyroid microsomal antibodies. The percentage and absolute number of total T-lymphocytes (OKT3+) and OKT4+ cells significantly decreased during pregnancy in patients with Graves' disease and in normal women. Post partum, OKT3+ and OKT4+ cells returned to pre-pregnancy levels in both groups. In Graves patients and in controls, the percentage and absolute number of OKT8+ cells during pregnancy and post partum were not significantly different from pre-pregnancy levels. Lastly, the OKT4+/OKT8+ ratio, which decreased in normal subjects at the three sampling times during pregnancy, decreased only in the last two trimesters of pregnancy in patients with Graves' disease.
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The mechanism by which hypoxia abolishes the tachyarrhythmias induced by cardiac steroids was studied in cardiac Purkinje and ventricular muscle fibres. In muscle fibres, hypoxia reduces excitability markedly, reduces the size and increases the time to peak of the oscillatory potentials (Vos) and of the aftercontractions induced by cardiac steroids, thereby abolishing the tachyarrhythmias. In Purkinje fibres, hypoxia also decreases Vos and excitability but abolishes the tachyarrhythmias only if repeated or prolonged. In Purkinje-muscle preparations, hypoxia blocks impulse conduction from the fast discharging Purkinje fibres to the myocardial fibres when the latter are still little intoxicated. It is concluded that hypoxia affects promptly ventricular muscle fibres and (depending on the experimental conditions) Purkinje fibres also, and readily blocks impulse transmission to muscle fibres. Hypoxia abolishes arrhythmias by decreasing Vos size (probably through an impaired calcium uptake into the sarcoplasmic reticulum), by causing a conduction block at the Purkinje-muscle junction (probably through an increase in cytoplasmic calcium) and by reducing excitability.
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The effect of anaesthesia with atropine and pentobarbital (PB) in three groups of volunteers has been tested. The dose used for the anaesthesia was 20 mg/kg body weight of PB. The experiment was performed with and without stimulation test with GnRH. Anaesthesia was shown to increase serum levels of LH and to increase the response to stimulation with GnRH. Atropine and mental stress seem to have no effect on the hormones. No variation in serum levels of FSH in the anaesthesized volunteers was noted. The data obtained have been statistically controlled.
The Authors have tested serum levels of CEA, ferritin, Alpha-1-antitrypsin, parathyroid hormone (PTH) and calcitonin (CT) in 286 patients affected by lung, gastrointestinal, breast and other kinds of cancer and by non neoplastic diseases. 50 healthy subjects were tested as matched controls too. None of the tested patients was subjected to blood transfusion, therapy with iron, radio- or chemotherapy before the blood drawing. Cea, ferritin, PTH and CT were tested by radioimmunoassay; AAT by laser nephelometry. All the healthy subjects showed serum levels of the markers in the normal ranges. Also the percent of cases with contemporaneous pathological markers was examined. The obtained data have been statistically controlled with "chi square" test. The results show that CEA, ferritin, AAT and CT are higher in the tumor groups than in the others. On the contrary PTH seems to be not useful as tumor marker. The Authors conclude affirming that it is not possible to use any of the tested substances as a specific tumor marker but it is useful to test at the same time these markers in the patients suspected to be affected by cancer for an early diagnosis and therapy, as there are few false positive and false negative cases.
The Authors examined 20 voluntary women without endocrine diseases. The women took 4 mg of metergoline orally and 30-60-90-120-180-240 minutes after the medicament was given the serum prolactin levels were tested. After 3 weeks, 14 among 20 subjects repeated the test assuming during the 3 days before 50 mg of metoclopramide orally once a day. The Authors found a remarkable decline of prolactin serum levels after metergoline administration in all subjects. After metoclopramide administration prolactin serum levels increased meaningly. Metergoline administration gave again considerable fall of prolactin serum levels in the 14 subjects. From the data the Authors affirm that metergoline inhibits prolactin secretion with an antiserotonine action
The effect of the surgery on the TSH and on the extra thyroid T4 metabolism was studied in thirty euthyroid patients. The TSH showed a light increase thirty minutes after the skin cut. There were no remarkable changes of T4 serum levels, while the serum triiodothyronine concentration fell during and after the operation, with a concomitant rise in reverse triiodothyronine.