Effect of chronic inhibition of converting enzyme on renal handling of salt and water: a study on a pediatric population.

BACKGROUND/AIMS: The effect of angiotensin-converting enzyme inhibition (ACEi) is amply documented in several pathological conditions. However, there are few reports about the effect of chronic ACEi on salt and water balance.The present work evaluates the effect of chronic ACEi on salt and water balance in a population of children receiving enalaprilchronically in order to reduce albuminuria elicited by auremic hemolytic syndrome. METHODS: Nine children aged from 9 to 19 years with normal glomerular filtration rate, normotension and with urinary concentration capacity preserved were treated with enalapril with doses ranging between 0.1 and 0.30 mg/kg/day. Diuresis, urinary absolute and fractional excretion of Na(+), K(+) and urea, creatinine clearance,osmolal clearance and tubular water reabsorption were measured under three experimental procedures: (1)with free access to water; (2) with a water load and (3) with water restriction. In the last group urinary antidiuretic hormone(ADH) was measured. These tests were performed ina paired way, just before starting ACEi treatment and after 6 months of enalapril treatment. RESULTS: Enalapril treatment diminished the urinary concentration capacity without affecting Na(+) and K(+) urinary excretion. Creatinine clearance was not modified except in the condition of water load where a fall in it was found after ACEi. ADH increased after enalapril treatment in children under water restriction. CONCLUSION: In these children chronic ACEi decreases urinary concentration capacity.

Thioacetamide impairs retinol storage and dolichol content in rat liver cells in vivo.

The aim of this paper was to ascertain whether chronic pretreatment with thioacetamide (TAA) might alter the uptake of a load of retinol and dolichol distribution in hepatocytes (HC), hepatic stellate cells (HSC) (Ito-1 and Ito-2 subfractions), Kupffer (KC) and sinusoidal endothelial cells (SEC). The reason why retinol and dolichol content was studied is that their metabolism and transport might be interrelated and that the two isoprenoids might exert different functions in the cells of the hepatic sinusoid. Rats were treated for 2 and 4 months with TAA, a known fibrogenic hepatotoxin, at a low dosage, to produce an early stage of damage. Three days before sacrifice, the rats were given a load of vitamin A, and cells were isolated to investigate its uptake. In HC, the load of retinol was taken up and accumulated, while a decrease in dolichol preceded retinol increase. In HSC, much less of the retinol load was stored than in controls, and dolichol content also decreased. Various minor modifications were seen in KC and SEC.Collectively, the results show that the distribution of these two isoprenoids, which play important roles in cellular differentiation and proliferation, is differently altered in the multiple cell types that line the hepatic sinusoid, and that both isoprenoids seem to participate in the first steps of liver damage.

Tumor necrosis factor concentrations in hemolytic uremic syndrome patients and children with bloody diarrhea in Argentina.

Hemolytic uremic syndrome (HUS) is thought to be a vascular endothelial injury disease. The mechanism of injury is unknown although verocytotoxins (Shiga-like toxins (SLTs)) are known to be associated with it. Recent evidence suggests that in vitro treatment of some endothelial cells with tumor necrosis factor alpha (TNF-alpha) dramatically increases their susceptibility to SLTs. We studied 25 children with HUS, 63 children with SLT-positive bloody diarrhea, 62 children with bloody diarrhea not associated with SLTs and 39 children admitted for elective surgery, included as an age- and season-matched control group. The TNF-alpha concentrations were found to be significantly elevated in children with HUS (range, 1 to 95 pg/ml; geometric mean, 32.2 pg/ml) compared with the healthy controls (range, 0 to 53 pg/ml; mean, 12.5 pg/ml; P < 0.001). Because it is hypothesized that TNF-alpha elevation might precede development of HUS, we also studied children with blood diarrhea. The TNF-alpha serum concentrations were significantly higher during the first 10 days after onset of bloody diarrhea than after the first 10 days (P < 0.02). Such elevation could be associated with vascular endothelial glycolipid receptor up-regulation and increased susceptibility to the effects of SLTs.

Supraceliac aortofemoral bypass.

Increasing numbers of patients with aortoiliac disease are seen with contraindications to standard infrarenal aortofemoral reconstruction. Although axillofemoral bypass is possible in these patients, the decreased patency rate associated with this operation makes alternate procedures desirable. This report details our experience with prosthetic bypass from the supraceliac aorta to the femoral arteries in seven patients with limb-threatening ischemia of the lower extremity, all of whom had undergone multiple previous aortic operations. The operations were performed through thoracoabdominal or flank incision, and the preferred graft configuration consisted of a single Dacron tube from the aorta to the left groin with a standard subcutaneous femorofemoral graft to the right groin. No surgical deaths occurred. At 3 1/2 years' mean follow-up, there has been one graft limb occlusion that resulted in amputation for an overall life table patency and limb salvage rate of 93%. We conclude that supraceliac to femoral artery bypass is a useful procedure for the treatment of patients who have had multiple previous aortic reconstructions fail.

Dolichol and vitamin A content in rat liver Ito (perisinusoidal) cells.

Dolichol has been determined in many tissues but to date no data are available on liver Ito (fat storing) cells. In this note dolichol was determined in two subpopulations of liver Ito cells isolated from rats pretreated with vitamin A: Ito-1, vitamin A enriched and Ito-2, relatively poor of vitamin A. Differences were observed in the behaviour of the two fractions after vitamin A pretreatment of rats. In fact, in Ito-1 fraction dolichol increases with the increase of vitamin A, while in Ito-2 fraction it does not change significantly with the increase of vitamin A. These results, while confirming the heterogeneity of fat storing cells, are discussed as to the possible role of dolichol and vitamin A metabolism.

Dolichol and retinol content of rat liver sinusoidal cells after chronic monensin treatment.

Aim of this study was to ascertain whether an impairment of communication between parenchymal and non-parenchymal liver cells involves vitamin A intercellular transport. The following approach was adopted: liver cells were isolated from rats treated chronically with the hydrophobic ionophore monensin i.p. for 3, 5, and 7 weeks and their retinol and dolichol content was assessed. Monensin, which alters membrane flow, was used because it had previously been reported to induce liver steatosis, cholestasis and glycogenolysis after acute treatment and, by preliminary morphological examination, to impair vitamin A transport between stellate cells and hepatocytes. Dolichol was chosen as a biochemical marker because it is a membrane lipid that modulates the fluidity and permeability of the membranes that retinol must cross. After monensin treatment, a load of vitamin A was given to rats three days before sacrifice, to ascertain whether its uptake by sinusoidal liver cells was altered. The main result was a dolichol decrease in hepatocytes and in the Ito-1 subfraction. In this latter, monensin induced a decrease in dolichol content only after vitamin A load. Moreover, while the hepatocytes were able to take up a load of vitamin A normally, the Ito-1 subfraction was no longer able to store retinol. Therefore the polarised transport of retinol between hepatocytes and stellate cells seemed impaired. The behaviour of sinusoidal endothelial cells and Kupffer cells might be ascribed to the functions of these cells and is not significantly modified by monensin. In conclusion, the altered cross-talk between sinusoidal cells in liver pathology might involve retinol as well as cytokines. Different pools of dolichol might have a role in this membrane process in a hydrophobic environment.

Action of chronic CC14 on the retinol and dolichol content of rat liver parenchymal and non-parenchymal cells.

We studied dolichol, on account of its role in membrane fluidity and fusion, and retinol, on account of its behaviour in liver fibrosis, in isolated parenchymal and sinusoidal rat liver cells after CCl4 treatment for 3, 5 and 7 weeks. Retinol uptake was also investigated by administering a load of retinol three days before sacrifice. In hepatocytes, dolichol decreased and seemed to be the preferred target of lipid peroxidation by CCl4; indeed, retinol increased especially after vitamin A load. Two subfractions of hepatic stellate cells were obtained: in the subfraction called Ito-1, dolichol decreased, while the supplemented retinol was no longer stored; in the subfraction called Ito-2, the values were intermediate. In Kupffer and endothelial cells dolichol was higher after three weeks, in agreement with fibrogenesis. Retinol increased after retinol load, in Kupffer and endothelial cells, in agreement with their scavenger function. The different behaviour of dolichol content in parenchymal and non-parenchymal cells suggests that dolichol may have different functions in liver cells. Since it has been ascertained that, in liver fibrosis, stellate cells gradually lose retinol, the inability of HCs to send retinol to Ito-1 subfraction or the inability of Ito-1 subfraction to take up and store vitamin A might induce or contribute to the transformation of these cells into a different phenotype. This behaviour is discussed regarding the role of cellular and retinol binding proteins in intracellular retinol content. Moreover a role of dolichol in membrane fluidity and retinol traffic is hypothesised.

Repair of limited or segmental defects of the cervical esophagus with mucosa-lined flaps.

Repair of limited cervical esophageal defects can now be accomplished safely with mucosa-lined flaps. Free jejunal grafts have demonstrated excellent durability and function for circumferential defects. The axial cheek flap and laryngeal flap have also shown excellent functional results for noncircumferential defects. In addition, all three of these procedures offer the advantage of immediate reconstruction. The size of the esophageal defect, the physical condition of the patient, and the rehabilitative goals are critical in patient selection.

Effects of phenylephrine on tissue gas tension, bleeding, infection, and lidocaine absorption.

In an attempt to find a vasoconstrictor with less detrimental local and systemic effects than epinephrine, the effects of phenylephrine, a pure alpha agonist, on tissue gas tension, bleeding, infection rates, and lidocaine absorption were studied. All concentrations of phenylephrine significantly reduced tissue PO2 within 10 minutes of injection, and reduction of PO2 was dose-dependent. Phenylephrine 1:10,000 produced significant bacterial growth when simultaneously injected with 6 X 10(6) Staphylococcus aureus. Bacterial growth was insignificant with 1:20,000 phenylephrine and absent with 1:40,000 phenylephrine. Blood loss from a standard wound was significantly reduced at all concentrations of phenylephrine. Lidocaine absorption was significantly reduced with 1:20,000 and 1:40,000 phenylephrine. In a rat model, 1:40,000 phenylephrine significantly reduced blood loss and lidocaine absorption, produced minimal reduction of tissue PO2, and did not enhance bacterial invasion.

Use of IgG Avidity test in case definitions of toxoplasmosis in pregnancy.

A survey network for congenital toxoplasmosis (TOXO-NET) was set up in December 1996 in Piedmont (Italy). Participants were asked to classify the infections in pregnant mothers and newborns by the criteria of the European Network on Congenital Toxoplasmosis published by Lebech in 1996. Because the IgG Avidity test is largely employed as a 2nd level test in toxoplasmosis diagnosis and it could be helpful to date infection, the co-ordinators of TOXO-NET suggested including it in the "case definition" of "probable" infection and "unlikely" infection. 117 cases of toxoplasmosis in pregnancy divided into the risk categories under Lebech's criteria were re-examined using the "new" case definitions. 77 out of 117 (65.8%) Toxoplasma gondii infections during pregnancy could be defined with only one serum sample using the IgG Avidity test. The IgG Avidity test proved a useful method to classify the Toxoplasma gondii infections in pregnancy, especially when we had only one serum sample.

Interaction between monensin and CCl4 after chronic treatment: dolichol and retinol content of rat liver sinusoidal cells.

The aim of this investigation was to study retinol, which is known to decrease in hepatic stellate cells during fibrogenesis, and dolichol, which influences membrane fluidity and decreases in liver injury, in freshly isolated liver parenchymal and nonparenchymal cells after intoxication of rats with CCl4 combined with the ionophore monensin for 3, 5 and 7 weeks. To study the interrelationship between dolichol and vitamin A transport, a load of vitamin A was given to batches of rats 3 days before sacrifice. Monensin did not modify the action of CCl4 in hepatocytes. On administration of CCl4 and CCl4-monensin, dolichol decreased independently of vitamin A load, while retinol increased, especially when a load of vitamin A was given to rats 3 days before sacrifice. Hepatocytes appeared to no longer be able to export or metabolize vitamin A. In a subfraction of hepatic stellate cells (Ito-1 cells) dolichol always decreased, while retinol was no longer stored after each treatment; dolichol and retinol showed the same behavior but the decrease was more pronounced in monensin after vitamin A load and after 3 weeks. These data support the hypothesis that by modulating membrane characteristics, dolichol might be involved in intracellular or intercellular retinol transport and that altered transport between hepatocytes and Ito-1 cells might accompany liver injury. The data regarding another subfraction, Ito-2 cells, partly resemble those for the Ito-1 fraction and are in agreement with the heterogeneity of hepatic stellate cells. In Kupffer and sinusoidal endothelial cells, dolichol and retinol content was not homogeneous and was only slightly altered after the treatments. Monensin and CCl4 are not interactive. Although both drugs alter membrane lipids, their association allows some sinusoidal cell responses to be differentiated.

[The additive antiproteinuric effect of Enalapril and Losartan to normotensive patients with pathology proteinuria]. / Efecto antiproteinúrico del uso aditivo de Enalapril y Losartán en pacientes pediátricos normotensos con proteinuria.

UNLABELLED: The proteinuria is frequently the initial insult to the kidney and it usually followed by a progressive decline in the glomerular filtration rate. The angiotensin II mediate by glomerular permeselective function via the opening of large pores after elevations in transmembrane pressure and by acting on the glomerular pressure, too. There is evidence that angiotensin-converting enzyme inhibitors alone or with the angiotensin receptor-blockade may improve the glomerular size-selective function and the hemodynamic intrarenal accounted output of plasma proteins. We evaluated the Enalapril action only in two progressive doses (stage 1: 0.2 mg/kg/day and stage 2: 0.4 mg/kg/per day, respectively) and then we evaluated the combinated treatment (stage 3) with Enalapril (0.2 mg/kg/per day) + Losartan (0.8 mg/kg/day) in thirteen patients (2 female/ 11 male, mean age 12 yrs, r: 10y-16y) normotensive with middle or heavy proteinuria and normal glomerular filtration rate. The study lasted six months. In the three stages occurred decrease of the urinary protein, but only the stage 2 and 3 was significant (p < 0.05). And the three stages had significant reduction of the mean blood pressure, too (p < 0.05). On the other hand there has a good correlation between the less proteinuria and the descent of the mean blood pressure in the stage I (r: 0.75, p < 0.05) and the stage 2 (r: 0.70, p < 0.05), but this did not occur in the stage 3 (r: 0.37, p < 0.1). No patient had raise serum potassium; neither did they have decrease glomerular filtration rate or anaemia. CONCLUSION: The coadministration of Enalapril and Losartan was the most efficient treatment antiproteinuric effect. It was not only by the drug related reduction in systemic blood pressure. There weren't any adverse side effects in any patient dependent of the medication.

Protein and m-RNA expression of farnesyl-transferases, RhoA and RhoB in rat liver hepatocytes: action of perillyl alcohol and vitamin A in vivo.

We analysed the action, in rats in vivo, of the protein isoprenylation inhibitor perillyl alcohol (POH) and that of vitamin A, alone or in association, on m-RNA and protein expression of farnesyltransferases (FTases alpha and beta subunits) and their protein substrates RhoA and RhoB, in isolated hepatocytes. Combined administration of POH and vitamin A induced a sharp decrease in FTase alpha protein after 96 h, suggesting an involvement not only of farnesyltransferases but also of geranylgeranyltransferases, which share the FTase alpha protein. FTase beta protein did not decrease. POH plus vitamin A, in contrast with POH or vitamin A alone, induced a decrease in RhoB protein, probably because of different cleavages. No modification was observed in RhoA protein. Vitamin A alone increased RhoB m-RNA and protein expression. As one of the functions of RhoB is cell polarisation, these data support our previous hypothesis of a polarised transport of vitamin A from hepatocytes to hepatic stellate cells. As the behaviours of m-RNAs and proteins in this study were often different, cytoplasmic metabolic pathways must be considered for the parameters studied. The behaviour of Rho B, which is thought to have an antioncogene function, is discussed in view of its isoprenylated forms in the membranes. These preliminary findings stress the need, when studying the association of two isoprenoids in cancer therapy, to consider normal as well as tumour-bearing animals.

[Staphylococcal adherence to oral mucosal cells]. / Adesivita' degli stafilococchi alle cellule della mucosa orale.

The ability of Staphylococcus to adhere to human oral epithelial cells was studied. S. aureus and S. epidermidis showed remarkable attachment to cheek mucosal cells, comparable to adherence to nasal mucosal cells observed by other Authors. The same bacteria lowered consistently their ability to adhere when were previously cultured in human saliva.

[Bacterial antagonism of oral secretions towards staphylococci]. / Aspetti di antagonismo batterico nelle secrezioni orali nei confronti degli stafilococchi.

Bacterial antagonism may be one of the mechanism which regulates the bacterial flora of the pharynx. We have investigated the bacterial antagonism exerted in oral secretion by alpha-hemolytic streptococci against S. aureus and S. epidermidis. We cultured viridans streptococci and staphylococci in human saliva and we noted a bactericidal activity towards staphylococci. Such activity, referable to the salivary system (peroxidase-thiocyanate) activated by hydrogen peroxide produced by streptococci, was greater on S. epidermidis. The remarkable sensitivity of S. epidermidis could explain the rare presence of this species in pharynx and oral cavity.

[Preferential staphylococcal colonizing site in the upper airway]. / Sede preferenziale di colonizzazione degli stafilococchi nelle vie aeree superiori.

150 healthy individuals and 162 tonsillopathic patients were investigated for the presence of Staphylococcus species in the upper respiratory tract. S. epidermidis was isolated from the throat in a very small percentage of all the people examined. A great number of healthy individuals (40%) and of patients (70%) were colonized by S. aureus either in the nose or in the throat; 30% of the carriers harboured S. aureus exclusively in the tonsils and in the pharynx.