Intermittent contact mode AFM investigation of native plasma membrane of Xenopus laevis oocyte.

Intermittent contact mode atomic force microscopy (AFM) was used to visualize the native plasma membrane of Xenopus laevis oocytes. Oocyte membranes were purified via ultracentrifugation on a sucrose gradient and adsorbed on mica leaves. AFM topographs and the corresponding phase images allowed for visualization and identification of both oocyte plasma membrane patches and pure lipid bilayer regions with a height of about 5 nm within membrane patches. The quantitative analysis showed a normal distribution for the lateral dimension and height of the protein complexes centered on 16.7 +/- 0.2 nm (mean +/- SE, n = 263) and 5.4 +/- 0.1 nm (n = 262), respectively. The phase signal, providing material-dependent information, allowed for the recognition of structural features observed in AFM topographs.

Adhesion and proliferation of fibroblasts on cluster-assembled nanostructured carbon films: the role of surface morphology.

We have investigated the influence on adhesion and proliferation of NIH 3T3 fibroblasts of the surface morphology of cluster assembled carbon films deposited by Supersonic Cluster Beam Deposition. Nanostructured carbon films exhibit a multi-scale morphology, which resembles the surface structure of the extracellular matrix, and possess a high specific area, while being relatively smooth at all scales. Correlations between measured morphological parameters and adaptive cell response have been brought out. High specific area and smoothness appear to conceivably favour both the early attachment of plated cells and the long-term survival of adherent cells. Moreover, nano-structured carbon films affect the cells morphology as well as the extension and the number of the focal contacts.

[Colon recanalization after Hartmann's procedure. A challenge for the surgeon or a strategy to be changed?]. / La ricanalizzazione del colon dopo l'intervento di Hartmann. Un impegno per il chirurgo o una strategia da cambiare?

AIM: Restoration of colorectal continuity is the second step of the procedure originally described by H. Hartmann for the treatment of sigmoid colon cancers. It is a safe, but complex procedure, that needs a meticulous surgical technique and is associated with a significant morbidity in as many as 40% of cases. For this reason, many patients are not submitted to reversal of the colostomy. METHODS: The authors report their experience: 32 patients underwent colostomy closure after Hartmann's procedure during the last 8 years. RESULTS: The mortality rate was nil, but post-operative complications occurred in 12 patients (37.5%), namely: wound infection (11 patients) and anastomotic leak (2 patients). CONCLUSION: In light of this, it could be wiser to perform, in the patients affected with benign pathology, and in those affected with limited malignant pathology (T3), resection of the diseased segment of colon and primary anastomosis with temporary ileostomy, reserving Hartmann's procedure to patients unsuitable to one step treatment because of their poor general and local conditions.

[Laparoscopic cholecystectomy. Our clinical experience from 1994 to 1996]. / La colecistectomia laparoscopica. La nostra esperienza clinica dal 1994 al 1996.

BACKGROUND AND AIM: Videolaparocholecystectomy is now regarded as the gold standard of treatment for lithiasis of the gallbladder. METHODS: The authors report a retrospective of 258 consecutive videolaparocholecystectomies performed by the Surgical Division of Valduce Hospital in Como between 1994 and 1996. The authors describe the indications for VLC, techniques for the induction of pneumoperitoneum and the realisation of VLC and the percentage and caused of conversion. RESULTS: During this period a steady reduction was noted in the number of laparotomic cholecystectomies and a parallel increase in cholecystectomies performed using a laparoscopic technique (69.2 vs. 30.8% in 1994; 76.4 vs. 23.2% in 1995; 91.1 vs. 8.9% in 1996). A gradual extension of the indications for laparoscopic surgery can be seen leading to the application of this technique in patients suffering from acute cholecystic infection, hydros or empyema of the gallbladder. Conversion were required in 25 cases in this series (9.7%). During the last year analysed there were a total of 9 conversions (7.9%) even though the percentage of acute cholecystitis accounted for 38.9% of all cases of cholecystectomy. CONCLUSIONS: In line with the experience of other centres, the authors, currently propose VLC as the treatment of choice for lithiasic pathologies of the cholecyst.

Correction of a developmental defect in neutrophil activation and movement.

In order to more fully understand the mechanisms involved in the developmental defect in polymorphonuclear leukocyte (PMN) movement in human neonates, the authors have examined several events in the activation response sequence. Chemotactic factor receptor numbers have been found to be normal on the PMNs of neonates, but chemotactic factor-induced changes in membrane potential and cyclic adenosine monophosphate concentrations were markedly decreased to absent in the neonatal cells. Because the neonatal PMN lacks the ability to deform normally, we examined the effects of a methylxanthine derivative, pentoxifylline, on the responses of neonatal cells. This agent has been reported to increase cell deformability and improve cell movement. Pentoxifylline had an effect in improving chemotactic function in the PMNs of neonates, while correcting the abnormality in membrane potential. In addition, this agent was found to enhance the movement of cell surface concanavalin A receptors after colchicine treatment. These results suggest that this developmental defect in cell activation and movement may be an abnormality that can be corrected pharmacologically.

[Measurement of venous pressure by Doppler sonography: usefulness and limitations in saphenectomy]. / Misurazione della pressione venosa con la Doppler sonografia: utilità e limiti nell'intervento di safenectomia.

After a short mention on the many last methods for venous pressure measurement, the Authors presents a relatively new method of this measurement with the Doppler ultrasonography. They point out its utility with regard to safenectomy by a study on 42 patients whose, at the present, only 10 preliminary results are available. This results allow to verify the opportunity of to value preoperatory and precisely the pressure drop obtainable with the safenectomy.

Complement-dependent bactericidal activity for E. coli K12 in serum of preterm newborn infants.

Complement-dependent serum bactericidal activity for E. coli K12 was assessed in 12 term infants and in 16 preterm infants. In both groups of newborns, at birth, bactericidal reaction by the classical pathway of complement activation was impaired with respect to normal controls at less than 0.001 level of significance (as estimated by Student's t-test). The serum bactericidal reaction by the alternative pathway of complement activation was significantly impaired only in preterm newborns, being normal in term infants. At a time corresponding to 40 weeks' gestational age also in preterm newborns alternative pathway mediated bactericidal activity for E. coli K12 was found normal. Classical pathway mediated bactericidal activity became normal only at an age corresponding to 52 weeks' gestational age.

Abnormality in actin polymerization associated with defective chemotaxis in neutrophils from neonates.

In an attempt to determine the mechanism of the profound defect in chemotaxis observed in the neutrophils of human neonates, we have examined the generation of polymerized or filamentous actin (F actin) following stimulation of the cells with chemotactic factors. We have also examined the changes in the intracellular levels of free calcium in neonatal neutrophils and compared the results with those in adult neutrophils. Following exposure to formyl-methionyl-leucyl-phenylalanine (FMLP) or zymosan-activated serum (ZyAS), neutrophils from adult donors showed an increase in intracellular free calcium, as determined by Quin 2/AM fluorescence, and in actin polymerization (45-55%), as measured by nitrobenzoxadiazole phallicidin fluorescence. These responses were abolished by preincubation with the calcium antagonist verapamil (0.1 mM), which inhibits both calcium influx and release from intracellular stores. In marked contrast to the results obtained with neutrophils from adults, neutrophils from newborn infants, which have defective chemotactic responses, failed to generate F actin following FMLP or ZyAS stimulation and developed significantly lower levels of free intracellular calcium.

Inhibition of lymphocyte and neutrophil chemotaxis by pertussis toxin.

The cells of the mammalian immune system possess special migratory properties within their in vivo environment, a surveillance characteristic that is thought to be important in the protection of the organism from transformants and exogenous pathogens. Pertussis toxin (PT) has been shown to disrupt the intensity of this process by seriously affecting lymphocyte recirculation in vivo. The mechanisms responsible for this inhibition were investigated by using the in vitro model systems of polymorphonuclear leukocyte and lymphocyte chemotaxis. The type of inhibition that was observed in these in vitro assay systems was quite similar to that observed in vivo, because PT could depress chemotaxis in vitro as well as the accumulation of radiolabeled lymphocytes and neutrophils within a peripheral site of inflammation in vivo. The alterations in neutrophil motility were found to be associated with a stimulus-specific inhibition of the triggering of superoxide anion generation and lysosomal secretion. Some inhibition of neutrophil adherence to plastic surfaces was also observed, most notably after augmentation of adherence with the chemoattractant fMLP. The observed alterations in cellular function after PT treatment occurred in the absence of defects in chemoattractant binding to the neutrophil cell surface, or of membrane potential changes stimulated by ligand binding. The effect of PT in this system was found to be associated with an abnormality in the regulation of intracellular free calcium, suggesting that the substrate for PT in neutrophils is involved in the regulation of calcium ion channels.

[Uterine multiple node fibromyomatosis associated with an asymptomatic leiomyoma of the small intestine]. / Fibromiomatosi uterina a nodi multipli associata a leiomioma asintomatico del tenue.

Benign small bowel tumours are rare, often asymptomatic and are founded incidentally at surgery or post mortem examination. In about 70% patients with benign small bowel tumour were reported to have associated benign or malignant tumours of other districts. The Authors report a case of leiomyoma of the small intestine associated with multinodular leiofibromyomatosis of the uterus.

Influence of ceftriaxone on natural defense systems.

The in vitro and in vivo effects of ceftriaxone, a newly developed cephalosporin, on phagocytes and T-cell subsets were studied. Ceftriaxone in vitro did not interfere with phagocytosis, phagocytosis-dependent metabolic activation, and microbicidal activity (against Staphylococcus aureus and Candida albicans) of human neutrophils at doses ranging from 10 to 320 micrograms/ml. In vitro chemotaxis was markedly inhibited both in the presence of and after 30 minutes of exposure to 40 micrograms/ml of ceftriaxone. Six normal adult volunteers were given 2 g of antibiotic intravenously every 24 hours for six days. The in vivo effects of ceftriaxone on neutrophil functions and T-cell subsets were investigated before and 30 minutes after injection on the first and third days. No change in any phagocyte function (chemotaxis, phagocytosis, phagocytosis-dependent metabolic activation, and microbicidal activity) or in the distribution of T-cell subpopulations was observed.

Defective membrane potential changes in neutrophils from human neonates.

In an attempt to determine the mechanism of the profound defect in chemotaxis observed in the polymorphonuclear leukocytes (PMN) of human neonates, we have examined membrane potential changes and alterations in free intracellular calcium following chemotactic factor stimulation. Following exposure to formyl-methionyl-leucyl-phenylalanine (FMLP), PMN from adult donors (11) showed a marked change in membrane potential (31%) as determined by fluorescence emission using the cyanine dye, 3-3-dipentyloxacarbocyanine [DiOC5(3)]. In marked contrast, FMLP-stimulated PMN from 10 human neonates failed to show any significant change in membrane potential (1-2%). Using the calcium-sensitive probe Quin 2/AM, FMLP induced an increase in fluorescence of up to 51% in adult PMN (10). In contrast, the change in intracellular free calcium induced in neonatal PMN was much less (32%; P less than 0.01). These results suggest that the profound defect in chemotactic responsiveness of PMN from human neonates may result from an inability of these cells to undergo changes in membrane potential following inflammatory mediator stimulation.

Defective phagocyte Aspergillus killing associated with recurrent pulmonary Aspergillus infections.

An apparently healthy boy was suffering from recurrent Aspergillus infections. No classical conditions of immunodeficiency were found. Studies on the patient's phagocytic system revealed neutrophils and monocytes to function normally except in Aspergillus killing (microbicidal activity for bacteria and Candida was normal). Aspergillus killing mechanisms may be complex and peculiarly selective, possibly involving both oxygen-dependent and independent mechanisms.

Defective neutrophil motility in children with chronic liver disease.

Neutrophil motility was assessed in 31 children with chronic liver disease to estimate the eventual increased susceptibility of these patients to bacterial infections. Twelve children had chronic hepatitis (seven with chronic persistent hepatitis and five with chronic active hepatitis), which was mostly related to hepatitis B virus (HBV) infection. Nineteen children had chronic intrahepatic or extrahepatic cholestasis. A total of six serious bacterial infections occurred in four of the 31 patients during the study. Twenty of the 31 children had a persistent defect of neutrophil chemotaxis. This defect was found in four types of childhood chronic liver disease: HBV-related chronic hepatitis and idiopathic intrahepatic cholestasis of infancy, in which the defect did not seem to predispose significantly to bacterial infection, and in Byler's disease and biliary atresia, in which this neutrophil defect was associated with an increased frequency of severe infections.

Effect of beta-lactam antibiotics on migration and bactericidal activity of human phagocytes.

The effect of beta-lactam antibiotics upon some functions of human phagocytes was examined. Penicillins (carbenicillin and piperacillin), thienamycin, and cephalosporins (cefotetan, ceftazidime, and moxalactam) had no effect on either the random or directional migration or on the bactericidal activity of neutrophils and monocytes against Staphylococcus aureus. On the contrary, cefoperazone at therapeutic levels was shown to inhibit neutrophil chemotaxis.

[Stomach diverticula. Endoscopic contribution]. / I diverticoli dello stomaco. Contributo dell'endoscopia.

Four cases of gastric diverticula culled from a series of about 3600 oesophagogastroduodenoscopies performed at the digestive endoscopy service of the Valduce Hospital, Como, between 1977 and 1980 are discussed. In the first case, the diverticulum involved the fundus; in the second, a small diverticulum of the greater curvature was combined with postpyloric substenosis that could not be passed by the instrument; in the third, a diverticulum of the fundus was accompanied by a 0.5 cm diameter polyp on the greater curvature; in the fourth, a diverticulum of the fundus was accompanied by a small diverticulum near the duodenal ampulla. Stress is laid on the usefulness of endoscopy in both diagnosis and treatment, as a means of distinguishing cases open to medical management from those that can be more profitably treated surgically.