The pattern of gastroesophageal reflux in asthmatic children.

The association between gastroesophageal reflux (GER) and asthma is not fortuitous. The objective of our study was to test a group of children with asthma by, 24 hr gastroesophageal pH monitoring and to relate the results to the patients medical history and clinical data. We studied 77 children aged from 39 to 170 months suffering from particularly recurrent and/or therapy-resistant asthma. Medical history data were collected for each patient and included: severity and characteristics of respiratory symptoms, presence, if any of allergy; presence, if any, of GER-related symptoms; and presence, if any, of esophagitis-related symptoms. Esophageal pH was measured by 24 hr computerized monitoring of the main measures in all patients. Forty-seven children were also examined by gastroesophageal endoscopy. The prevalence of GER was 61% on the basis of the reflux index (cutoff: 4.2%). Gastroesophageal reflux in these asthmatic children was characterized mainly by short-lasting daytime episodes. The patients tended to present GER mainly associated with vomiting but not with signs and symptoms of esophagitis. The short-lasting nature of the reflux episodes demonstrates good esophageal clearance. The time of onset of respiratory symptoms (day/night) was not associated with any particular type of GER, the severity of which tends to be proportional to the seriousness of the asthma. No correlation was found between GER and allergy. No statistically significant differences were found in clinical or medical history findings between patients with pathologic and nonpathologic GER.

Channel formation by salmon and human calcitonin in black lipid membranes.

In this study we investigated the interaction of salmon and human calcitonin (Ct) with artificial lipid bilayer membranes. Both peptides were able to form either transient or permanent channels in the model membranes. The channels formed by salmon Ct at concentration (125 nM) had, on average, a single-channel conductance of 0.58 +/- 0.04 nS in 1M KCl (+10 mV), which is voltage-dependent at lower voltages. Human Ct forms at the same concentration channels with a much lower probability, and high voltages of up to +150 mV were needed to initiate channel formation. The estimated single-channel conductance formed under these conditions was approximately 0.0119 +/- 0.0003 nS in 1 M KCl. Both salmon and human Ct channels were found to be permeable to calcium ions. The possibility is discussed that the superior therapeutic effect of salmon Ct as a tool to treat bone disorders, including Paget disease, osteoporosis, and hypercalcemia of malignancy, rather than human Ct is related to the lack of the fibrillating property of salmon Ct. Preliminary data indicate that also eel and porcine Ct and carbocalcitonin form channels in model membranes.

Studies of mitochondrial porin incorporation parameters and voltage-gated mechanism with different black lipid membranes.

Our work in general aims to clarify the mechanism of what can be considered as a process of the kinetics of porin incorporation into bilayer planar membranes and to identify the parameters involved. In this paper, we report the results of systematically investigating the kinetics of porin incorporation into bilayer membranes made up of phosphatidylinositol or oxidized cholesterol using a simple and low-cost ac method. By means of a mathematical model, we provide evidence that two concurrent processes are present during the kinetics which can be interpreted as positive/negative cooperativity, and we investigate the parameters' dependence on external applied voltages. We observed a phase transition (or similar phenomenon) which seems to take place during the insertion process. The conductance measurement obtained by using data at the steady state conditions, provided indirect indications of two possible gating mechanisms.

[Adolescents and celiac disease: psychological aspects]. / L'adolescente e la malattia celiaca: aspetti psicologici.

Many studies have been carried out on different aspects of coeliac disease in children and adolescents. However, little has been done on how these patients experience their situation and how they cope with dietary treatment. A group of 39 children and adolescents with coeliac disease participated in a controlled questionnaire study. Conclusions are that the acceptance of a gluten-free diet is problematic for the majority of children and adolescents affected by coeliac disease; in particular in the 12 to 17 year old group, that is in that period of life in which the individual tends to oppose the adult world, in search of an individual personality. This search is disturbed in the majority of coeliac patients. The feelings of difficulty connected to the gluten-free diet appear to be almost absent in the family environment, whereas they emerge significantly at times of meeting and sharing with friends.

Pore formation in lipid bilayer membranes made of phosphatidylinositol and oxidized cholesterol followed by means of alternating current.

The kinetics of porin incorporation into black lipid membranes (BLM) made of phosphatidylinositol (PI) or oxidized cholesterol (Ox Ch) were studied by means of alternating current; the set-up was able to acquire resistance and capacitance simultaneously by means of a mixed double-frequency approach at 1 Hz and 1 KHz, respectively. Conductance was dependent on the interaction between protein-forming pores and lipids. For PI membranes below a porin concentration of 12.54 ng/ml, there was no membrane conductivity, whereas at 200 ng/ml a steady-state value was reached. Different behavior was displayed by Ox Ch membranes, in which a concentration of 12.54 ng/ml was sufficient to reach a steady state. The incorporation kinetics when porin was added after membrane formation were sigmoidal. When porin was present in the medium before membrane formation, the kinetics were sigmoidal for PI membranes but became exponential for Ox Ch membranes. Furthermore, for BLM made of PI, the conductance-versus-porin concentration relationship is sigmoidal, with a Hill coefficient of 5.6 +/- 0.07, which is functional evidence corroborating the six-channel repeating units seen previously. For BLM made of Ox Ch, this relationship followed a binding isotherm curve with a Hill coefficient of 0.934 +/- 0.129.

Effect on cortical and trabecular bone mass of different anti-inflammatory treatments in preadolescent children with chronic asthma.

Bone metabolism and density have been shown to be abnormal in adult asthmatic patients treated with inhaled corticosteroids. Because the largest increases in bone growth and mineral deposition occur during childhood and adolescence, we performed a cross-sectional evaluation of cortical and trabecular bone mass by dual-photon absorptiometry at the proximal one third of the radius (cortical bone) and by dual-energy X-ray absorptiometry at the L2-L4 lumbar spine (trabecular bone) in 64 prepubertal asthmatic children receiving beclomethasone dipropionate (BDP) or cromolyn sodium (CS). Dual-energy X-ray absorptiometry was performed by anteroposterior scan and also by lateral vertebral scan in order to exclude the posterior elements of the vertebrae, which are composed mainly of cortical bone and which are less sensitive to the negative effect of steroids. Furthermore, we calculated "volumetric" bone density, dividing lateral mineral content by the vertebral volume. Bone mineral areal density and volume bone density did not differ in children receiving BDP for 6.7 +/- 1.3 mo at a mean dose of 319.3 +/- 130 micrograms/d compared with those in children treated with CS. Furthermore, anteroposterior bone density in our study population was in agreement with published normative data and with that of normal age-related healthy nonasthmatic children living in the same area and with the same dietary intake of calcium. No normal values are available for lateral and calculated-volume bone density. In conclusion, treatment with BDP does not appear to have an adverse effect on bone mass in prepubertal children with mild moderate asthma. Longitudinal studies should be performed in order to evaluate the effect of early introduction of inhaled corticosteroids in children with mild asthma.

Potentiation by m-cresol on transepithelial sodium transport across frog skin induced by insulin.

1. In this study we found that insulin mixed with m-cresol, normally used as pharmaceutical preparation, shows an earlier and larger stimulating effect on transepithelial sodium transport than insulin alone. 2. The action displayed by the m-cresol seems to be specific for insulin because m-cresol mixed with ADH, a hormone known to stimulate sodium transport, failed to show the potentiation seen for insulin. 3. It is proposed that m-cresol could facilitate the interaction with its receptor by modifying the insulin molecule. 4. This finding could be of biological and pharmacological importance.

The effect of ADH and insulin on active sodium transport across frog skin in the presence of alternariol mycotoxin.

1. The effect of vasopressin and insulin on active sodium transport across frog skin in the presence of internal alternariol mycotoxin was studied, using the short-circuit technique. 2. Vasopressin stimulates sodium transport across frog skin by decreasing the resistance to sodium entry into the epithelial cells, thus partially removing the inhibition on the short-circuit current due to the action of Alternariol mycotoxin. 3. Even insulin which is known to increase the short-circuit current by a different mechanism, determines a rapid reversal effect on the inhibition due to Alternariol. 4. These data confirm the different action of the two hormones on active sodium transport across frog skin, and furthermore are indicative of an inhibition of transepithelial sodium transport by Alternariol mycotoxin probably via the sodium pump.

The effect of T-2 toxin on active sodium transport across frog skin in the presence of ADH and amphotericin B.

1. The effect of T-2 toxin on active sodium transport across frog skin both in the presence and in the absence of stimulants of sodium transport, such as Amphotericin B and ADH, was studied using the short circuit current technique with the following results. 2. T-2 toxin produces inhibition of active sodium transport in a dose-response correlation. 3. This effect is irreversible since the washing out of the tissue does not restore its functionality. This indicates that the micotoxin may cross the cellular membrane and act on the internal site. 4. ADH partially removes the inhibitory effect of T-2 toxin. 5. The increase of the sodium pool in the cell as determined by Amphotericin B does not reverse the inhibitory effect of T-2 toxin. 6. The biological significance of these data is discussed in regard to the possible effect of T-2 toxin on Na+, K+-ATPase activity either directly or by a reduction in the metabolic supply of substrates, or by a modified stoichiometry of the pump reaction.

[Effects of dihydrostreptomycin and gentamycin on platelet membrane Na+-K+ATPase]. / Azione della diidrostreptomicina e della gentamicina sulla Na+-K+ATPasi di membrana piastrinica.

The use of aminoglycosides is characterised by a bound linkage between therapeutic and toxical levels. The aim of our study was to define the influence of diidrostreptomicin and gentamicin over Na+-K+ATPase of membranes of platelets. In this study, Bounting's and Caravaggio's method has been used, while ATPase activity was expressed in n mol of hydrolized ATP/min/mg of proteins. The data so obtained showed that the antibiotics were able to block up ATPase activity.

Effect of aminoglycoside antibiotics on sodium transport across the Rana esculenta urinary bladder.

The aminoglycoside antibiotics inhibit the short circuit current (s.c.c.) in the urinary bladder of Rana esculenta. This effect is due to a direct inhibition on the sodium pump; ADH or db-AMPc are not able to reverse the inhibition of the sodium current, but are effective in stimulating the urea fluxes in the presence of antibiotics. In correlation with the number of the NH+2 groups in the antibiotic molecule there is a different pattern of inhibitory effect, i.e. neomycin greater than gentamycin greater than dihydrostreptomycin greater than kanamycin greater than spectinomycin.

Interaction of the aminoglycoside antibiotic dihydrostreptomycin with the H+-ATPase of mitochondria.

In this paper a study is presented of the effect of dihydrostreptomycin on the H+-ATPase of the inner mitochondrial membrane. The antibiotic caused at concentrations of 1-5 X 10(-3)M a marked enhancement of the hydrolytic activity of the H+-ATPase complex in intact mitochondria and submitochondrial particles which was accompanied, in the latter, by enhancement of passive transmembrane proton conduction by the complex. The stimulation by dihydrostreptomycin of ATP hydrolysis resulted in a suppression of the sensitivity of this activity to inhibition by oligomycin. On the other hand the dihydrostreptomycin-promoted proton conduction in submitochondrial particles was suppressed by oligomycin. At concentrations above 10(-2)M dihydrostreptomycin caused inhibition of the activity of both membrane bound and isolated H+-ATPase. In submitochondrial particles devoid of the catalytic moiety (F1) of the H+-ATPase complex, dihydrostreptomycin caused partial inhibition of proton conductivity. It is concluded that the antibiotic uncouples the hydrolytic activity of the catalytic moiety (F1) from transmembrane proton conduction by the membrane sector (F0) of the ATPase complex. This effect can be followed at higher concentrations of dihydrostreptomycin by inhibition of the catalytic activity of F1 and, when F1 is removed from the membrane, by inhibition of transmembrane proton conduction by F0.

Serosal and mucosal facilitated transport of urea in urinary bladder of of Bufo bufo: evidence for an alleged water uptake.

In Bufo bufo urinary bladder an urea facilitated transport has been localised on the luminal membrane. The transport fulfils the criteria for such a mechanism, i.e. is saturable and is inhibited by phloretin, a specific inhibitor for urea transport. Similarly to that of Bufo marinus and Rana esculenta the luminal membrane of Bufo bufo urinary bladder shows an ADH stimulated facilitated transport. Experiments wtih Amphotericin B, serosal phloretin (with and without ADH), have demonstrated the presence of a facilitated urea transport localised on basolateral membrane. Urea uptake on the isolated epithelial cells of Bufo bufo urinary bladder shows a characteristic feature, different from molecules passively transported such as glycerol yet inhibited by phloretin. Allegedly with urea, water flows in to the cells by a dragging or osmotic effect.

[Evidence of morphological modifications induced by theophylline in the urinary bladder epithelium of Rana esculenta]. / Evidenze di alcune modificazioni morfologiche indotte dalla teofillina sull'epitelio vescicale di Rana esculenta.

This preliminary work concerns the morpho-functional action induced by Theophylline on bladder epithelium. The epithelium treated with Theophylline shows important structural variations. The whole tissue thickness appears reduced with cell disposed in monostratified layer. They show a light grade of swelling with nucleus and cytoplasm less evident and boundary less marked. It is important to note that the permeability of the epithelium does not appear modified.

Non-electrolyte permeability through black lipid membranes with different surface charge.

The permeability coefficients of some non-electrolytes has been measured across black lipid membranes of different composition. Large discrepancies between permeability coefficients and oil-water partition coefficients has been observed. The discrepancy level seems to be related to the degree of organization of the membrane.