G. Di Pasquale

Thyroid function in children with cystic fibrosis

Serum concentrations of T4, T3, reverse T3 (rT3), TSH, Thyroxine binding globulin (TBG) and Thyroxine binding prealbumin (TBPA) were measured and a TRH-stimulation test was performed in 10 iodide untreated children affected by cystic fibrosis (CF) and in 84 controls.As compared to the controls, CF patients had lower T4 and rT3, similar T3 and TBG and increased T3:T4 ratios. They also had lower TBPA, but this could not account for the low T4. Finally they had higher basal and TRH-stimulated TSH. Our results indicate subclinical hypothyroidism in CF. The mechanisms responsible for this situation are not elucidated by our data.

TTF-2/FOXE1 gene polymorphisms in Sicilian patients with permanent primary congenital hypothyroidism.

Thyroid transcription factor-2 (TTF-2/FOXE1) is a polyalanine domain protein that regulates thyroid embryogenesis, but very few patients with permanent primary congenital hypothyroidism (pCH) harbor germline mutations of this or other transcription factors that are involved in thyroid development that might explain the etiology of pCH. Variations within the polyalanine tract are found in a variety of genes and are often reported in association with malformation syndromes; pCH is frequently associated with thyroid malformations and extra-thyroidal malformations. Therefore, in this study we investigated whether alanine (Ala) length polymorphisms and non-polymorphic mutations of the TTF-2 gene in pCH patients might be involved in the pathogenesis of pCH. The entire coding region of the TTF-2 gene was analyzed in 57 Sicilian patients and 142 healthy controls. We found that the homozygous Ala14 polymorphism (Ala14/14) was less frequent in the pCH group than in the controls. In contrast, significantly more pCH patients than controls harbored the Ala16 polymorphism (Ala16/16 and Ala14/16). However, neither the Ala14/14 nor the Ala16 polymorphism was related to extra-thyroidal malformations. Two of the 57 patients carried Ala11/14 and Ala12/14, and one Ala14/14 patient also had the silent polymorphism 387 C/T (Leu129Leu). Other than known polymorphic variants we found no mutation in the TTF-2 gene. Therefore, this study demonstrates that mutations in the TTF-2 gene are rare in pCH patients and suggests that variations in the length of the Ala-tract could at least partially explain the etiology of pCH but not that of extra-thyroidal malformations.

Effect of interleukin 8 and ICAM-1 on calcium-dependent outflow of K+ in erythrocytes from subjects with essential hypertension.

SUMMARY Introduction: The pathogenic mechanisms underlying the increase in peripheral resistance and the contraction of smooth muscular fibre cells in essential hypertension are not yet clearly understood. However, it is now known that immune system activation plays a role in the pathogenesis of some forms of arterial hypertension, and recent data show that the Ca2+ influx in some cells (i.e. red blood cells, leukocytes, platelets, smooth muscular fibre cells) is increased in subjects with essential hypertension, thus revealing a possible alteration in cellular membrane. The end-points of this study were therefore to ascertain whether red blood cells used as a cellular membrane model have a greater Ca2+ dependent K+ flow (Gardos effect) in hypertensive patients than in normotensive controls, to point out a different regulation of ionic channels, and whether IL-8 and the adhesion molecule ICAM-1 influence the membranous outflow. Material and methods: The study was conducted on 87 Caucasian subjects. Of these, 50 (25 men, 25 women; mean age 43 ± 3 years, mean body mass index (BMI) 27 ± 0.5 and 22.3 ± 0.3 kg m2, respectively) had mild-to-moderate hypertension (mean arterial blood pressure 120±8mmHg).The other 37 (18 men, 19 women; mean age 39 ± 3 years; BMI 23.8 ± 0.5 kg m2 and 22.8 ± 0.5 kg m2, respectively were normotensive healthy volunteers (mean arterial blood pressure 89 ± 2 mm Hg).All the patients and subjects were untreated for at least 4 weeks before blood sampling. Results: Ca2+-dependent K+ outflow was found to be greater in samples from patients with essential hypertension than in those from normotensive controls. lL-8 and ICAM-1 significantly enhanced the Ca2+-dependent K+ outflow in red blood cells from hypertensive subjects but had an inhibitory effect on cells from controls. In the experimental model, the presence of TMB-8, a membrane calcium antagonist, significantly reduced the Ca2+-dependent K+ efflux. Conclusion: Vasoconstriction in subjects with essential hypertension may therefore depend on a different regulation of ionic flow that probably supports an increased Ca2+ inflow in smooth muscle fibre cells. Under certain pathological conditions, some immune system components (i.e. interleukins, adhesion molecules) may directly enhance membrane permeability to Ca2+, thus inducing vasoconstriction in the smooth muscle cells.

Reduced Blood bcl-2 Protein Concentration in Patients on Hemodialysis

The concentrations of bcl-2 protein that can block programmed cellular death in various cell lines were evaluated in blood samples from 10 uremic patients on hemodialysis, 10 uremics not yet on hemodialysis, and in 10 healthy controls. The bcl-2 protein variations (in uremics on dialysis) were ascertained in patients during the dialysis session. Oxidative stress was evaluated in all groups by assaying the products of intraerythrocytic lipoperoxidation. Dialyzed and nondialyzed uremic patients had higher bcl-2 protein concentrations than healthy subjects. Dialysis causes a significant reduction in the concentrations of bcl-2 protein which becomes statistically significant during the 3rd hour. In both groups of uremic patients a positive correlation was found between bcl-2 protein and products of lipoperoxidation.

Transient electrocardiographic changes suggesting myocardial ischaemia in newborn infants following tocolysis with beta-sympathomimetics.

Serial electrocardiograms (ECGs) were studied prospectively in 80 apparently healthy newborn infants; 30 infants exposed in utero to prolonged tocolytic therapy (21 to ritodrine and 9 to isoxsuprine) and 50 infants non-exposed in utero to drugs (control group) matched for gestational age, Apgar score, and birth weight. Duration of exposure to tocolysis was at least 30 days (30–180 days) with an oral dosage of 10 mg 3 times daily. ECGs were graded for changes suggestive of ischaemia using the arbitrary grading system described by Jedeikin et al. [12]. In all infants with ECG features of myocardial ischaemia, serum creatine-phosphokinase iso-enzyme (CK-MB) activity was measured. Six out of 21 infants to ritodrine and six out of nine infants exposed to isoxsuprine showed a degree of ECG ischaemia which persisted for several weeks. No control infant presented grade 2 or 3 ECG changes after the 5th day of life. The results of this study seem to show that prolonged tocolytic therapy with β-sympathomimetics has side-effects on the fetal myocardium and suggest that this treatment be reserved only for selective cases and/or for short periods of time.

In Sicilian ethnic group non-classical congenital adrenal hyperplasia is frequently associated with a very mild genotype

The spectrum of mutated alleles in non-classical congenital adrenal hyperplasia (NC-CAH) has been recently reported to be very large and haplotypes may significantly differ in the different ethnic groups. In order to confirm that population differences may exist in the genetic basis of this disease, we have analyzed the genetic presentation of NC-CAH in a Sicilian cohort of symptomatic patients and compared our findings with the ones reported in other studies of different ethnic groups. In 38 NC-CAH patients coming from two regions of Sicily and born of Sicilian parents, we found that 84.2% of the chromosomes examined bore only mild mutations and only the remaining 15.8% of the chromosomes bore at least 1 severe mutation. The overall predominant mutation was V281L, which was detected in 73.7% of alleles and in 89.5% of patients. About 58% of the patients were homozygotes for this mutation. V281L allele and homozygote frequencies were higher in the present series than in other European and Italian reports. In our NC-CAH population, which is one of the largest ever reported, the patients with two mild mutations exhibited a less severe impairment of both clinical and endocrine phenotype. On the basis of these results we can conclude that: a) in Sicilian ethnic groups NC-CAH is frequently associated with a very mild genotype; b) the most frequent genotype in our series is V281L homozygosis; c) clinical and biochemical expression of NC-CAH is more marked in the patients bearing a severe mutation; d) no correlations between genotype and phenotype were found in our patients affected by NC-CAH.

AQP1 in Red Blood Cells of Uremic Patients during Hemodialytic Treatment

Hemodialysis influences the transport of water through the erythrocytic membrane, and induces morphologic and functional modifications. Recently water channels, called aquaporins (AQP), have been identified on the membrane of red blood cells. The aim of the present study was, therefore, to evaluate any relationships between volumetric changes in erythrocytes (MCV), plasma osmolarity and membrane expression of AQP1 in 22 uremic patients during a hemodialysis session, and compare value with those in a control group of 22 healthy volunteers. Membranal AQP1 expression was evaluated using three methods: indirect immunofluorescence under confocal microscopy, immunoenzymatic method after membrane extraction, and immunoblotting. In uremic subjects, at baseline membrane AQP1 expression was significantly lower, whereas plasma osmolality was higher than in controls. At 1 and 2 h of replacement therapy, a progressive increase was observed in erythrocytic AQP1, values similar to those in controls being attained after 3.5 h. During the session osmolality values reduced progressively, becoming significantly lower than basal values. The mean erythrocytic corpuscular volume in patients with ESRD was significantly lower than in cntrols at baseline. This value increased during hemodialysis, attaining statistical significance with respect to the basal value at 3.5 h of dialysis. Close correlations were found between plasma osmolality and AQP1 values (r = –0.930; p < 0.05), and also between MCV and plasma osmolality trend (r = –0.909; p < 0.05). There was a linear correlation (r = 0.63, p < 0.05) between plasma AVP concentrations and plasma osmolality. The variations found in plasma osmolarity during hemodialysis, may induce AQP1 expression on the membrane of intact red blood cells.