First synthesis of silicon nanocrystals in amorphous silicon nitride from a preceramic polymer.

We report the first synthesis of silicon nanocrystals embedded in a silicon nitride matrix through a direct pyrolysis of a preceramic polymer (perhydropolysilazane). Structural analysis carried out by XRD, XPS, Raman and TEM reveals the formation of silicon quantum dots and correlates the microstructures with the annealing temperature. The photoluminescence of the nanocomposites was investigated by both linear and nonlinear measurements. Furthermore we demonstrate an enhanced chemical resistance of the nitride matrix, compared to the typical oxide one, in both strongly acidic and basic environments. The proposed synthesis via polymer pyrolysis is a striking innovation potentially allowing a mass-scale production nitride embedded Si nanocrystals.

Identification of human tear fluid biomarkers in vernal keratoconjunctivitis using iTRAQ quantitative proteomics.

BACKGROUND: Understanding and treating vernal keratoconjunctivitis (VKC) has been a challenge because the pathogenesis is unclear and antiallergic therapy often unsuccessful. The aim of the study was to analyze peptide profiles in human tears using mass spectrometry to elucidate compositional differences between healthy subjects and patients affected by VKC. METHODS: Tears were collected from healthy subjects and VKC patients. Digested samples were treated with iTRAQ (isobaric tag for relative and absolute quantitation). Separation of tryptic peptides was realized using a MicroHPLC interfaced with a microfraction collector. MS and MS/MS mass spectra were performed using a MALDI TOF/TOF 4800 Applied Biosystem spectrometer. Protein Pilot™ software with Paragon™ algorithm v4.1.46 or GPS™ with Mascot engine was used as search engines with SwissProt or IPI human as the databases. RESULTS: A significant number of peptides were examined, and 78 proteins were successfully identified. In all VKC samples, levels of serum albumin, transferrin, and hemopexin were found up to 100 times higher than control tear levels and correlated to the severity of disease. Hemopexin, transferrin, mammaglobin B, and secretoglobin 1D were found significantly over-expressed in VKC samples compared with the control samples. Tear samples from patients treated with topical cyclosporine or corticosteroids showed a dramatic reduction in these protein levels. CONCLUSIONS: LC MALDI MS and isobaric tag for relative and absolute quantitation technique may be useful in the quantitative and qualitative characterization of the peptidoma of human tears. These techniques may identify target proteins to be used in the diagnosis and management of VKC and other inflammatory ocular surface conditions.

Endocytosis and intracellular localisation of type 1 ribosome-inactivating protein saporin-s6.

Saporin-S6 is a single-chain ribosome-inactivating protein (RIP) that has low toxicity in cells and animals. When the protein is bound to a carrier that facilitates cellular uptake, the protein becomes highly and selectively toxic to the cellular target of the carrier. Thus, saporin-S6 is one of the most widely used RIPs in the preparation of immunoconjugates for anti-cancer therapy. The endocytosis of saporin-S6 by the neoplastic HeLa cells and the subsequent intracellular trafficking were investigated by confocal microscopy that utilises indirect immunofluorescence analysis and transmission electron microscopy that utilises a direct assay with gold-conjugated saporin-S6 and an indirect immunoelectron microscopy assay. Our results indicate that saporin-S6 was taken up by cells mainly through receptor-independent endocytosis. Confocal microscopy analysis showed around 30% co-localisation of saporin-S6 with the endosomal compartment and less than 10% co-localisation with the Golgi apparatus. The pathway identified by the immunofluorescence assay and transmission electron microscopy displayed a progressive accumulation of saporin-S6 in perinuclear vesicular structures. The main findings of this work are the following: i) the nuclear localisation of saporin-S6 and ii) the presence of DNA gaps resulting from abasic sites in HeLa nuclei after intoxication with saporin-S6.

Effect of red pepper on symptoms of irritable bowel syndrome: preliminary study.

BACKGROUND: Abdominal pain, that characterizes irritable bowel syndrome (IBS) together with bloating and disordered defecation, is mainly related to a visceral hypersensitivity due to an increase of TRPV(1) nociceptive nerve fiber activity. AIM: As capsaicin contained in red pepper is able to desensitize the TRPV(1) fibres, we evaluated whether the red pepper oral administration can decrease the symptoms of visceral hypersensitivity in IBS patients. METHODS: The study was performed on 50 patients with IBS diagnosed following Rome II criteria. After a 2-week washout period, 23 patients were planned to receive 4 pills/day, for 6 weeks randomly and in a double blind manner, each containing 150 mg of red pepper powder with a coat that dissolves in the colon, and 27 patients placebo. The patients scored each day in a diary the abdominal pain and bloating intensities following the 5-point Likert scale. The weekly symptom mean scores and the final patient subjective evaluation on treatment effectiveness were statistically compared among groups and intra-groups with appropriate tests. RESULTS: Eight patients dropped from the study: 6 in the red pepper group for abdominal pain and 2 in the placebo group. In 8 patients, the pills were reduced to 2/day, because of the abdominal pain at the onset of treatment. The intra-group comparisons showed that in patients taking red pepper the abdominal pain and bloating mean score values of the last weeks of treatment were significantly improved with respect to pre-treatment values, unlike patients taking placebo. The final patient subjective evaluation on the treatment effectiveness showed that red pepper group scored significantly better than placebo. CONCLUSIONS: The results of this preliminary study indicate that the chronic administration of red pepper powder in IBS patients with enteric-coated pills was significantly more effective than placebo in decreasing the intensity of abdominal pain and bloating and was considered by the patients more effective than placebo.

Cytokines, matrix metalloproteases, angiogenic and growth factors in tears of normal subjects and vernal keratoconjunctivitis patients.

BACKGROUND: To detect the presence of multiple mediators and growth factors in tears of vernal keratoconjunctivitis (VKC) patients with active disease using stationary phase antibody arrays. METHODS: Tears were collected from 12 normal subjects (CT) and 24 active VKC patients. Tears were centrifuged and successively probed using three microwell plate arrays specific for: (i) cytokines: interleukin (IL)-2, IL-4, IL-5, IL-8, IL-10, IL-12, IL-13, interferon-gamma and tumour necrosis factor-alpha; (ii) growth factors: basic fibroblast growth factor (bFGF), platelet-derived growth factor, thrombopoietin, angiopoietin-2, vascular endothelial growth factor (VEGF), hepatocyte growth factor (HGF), keratocyte growth factor, tissue inhibitor of metalloprotease (TIMP)-1 and heparin-binding epithelial growth factor (HB-EGF) and (iii) matrix metalloprotease (MMP)-1, MMP-2, MMP-3, MMP-8, MMP-9, MMP-10, MMP-13, TIMP-1 and TIMP-2. RESULTS: Interleukin-8 signals were detected in all CT and highly detected in all VKC samples. The Th2-type cytokines, IL-4, IL-5 and IL-10 were detected only in tears of VKC patients. Signals for bFGF, HB-EGF, VEGF and HGF were detected in 41-87% of VKC samples and in few CT samples. Only TIMP-1 and TIMP-2 were found in all normal and patient tear samples, whereas MMP-1, MMP-2, MMP-3, MMP-9 and MMP-10 were highly present in all VKC samples. CONCLUSIONS: Stationary phase antibody array methodology was useful for the screening of various cytokines, growth factors and MMPs in tears. These analyses identified in tears of VKC patients previously unreported factors including MMP-3 and MMP-10 and multiple proteases, growth factors and cytokines, which may all play an important role in the pathogenesis of conjunctival inflammation.

Treatment of gastric emptying delay.

Gastric emptying delay is a rather frequent occurrence that may reveal itself with a broad spectrum of clinical manifestations, from slight dyspeptic symptoms up to alimentary vomiting. Once diagnosed with appropriate examinations, the treatment of this condition may be performed with a variety of means proportionate to the severity of the disease. In the first line there are dietetic measures and pharmacologic aids, that vary from currently available prokinetics drugs, drugs created for other therapeutical purposes, that reveal prokinetic properties, to new classes of prokinetics currently under clinical investigation or clinical trials. In more severe cases of gastroparesis, with vomiting and abdominal pain refractory to prokinetic therapy, other pharmacologic measures can be utilized, such as antiemetic and analgesic drugs. If the medical therapy is insufficient, endoscopic and surgical procedures are available, from the widening of the pyloric ring with botulinum toxin infiltrations or pneumatic dilatation, to the employment of various techniques of gastric electrical stimulation, up to partial or total gastric resection, when any other treatment fails and the patient is kept alive only with partial or total parenteral nutrition.

Allergy and the eye.

The eye represents an ideal and frequent site for the allergic reactions. The term 'allergic conjunctivitis' refers to a collection of disorders that affect the lid, conjunctiva and/or cornea. Even though the diagnosis is essentially clinical, local tests such as cytology, conjunctival provocation and tear mediator analysis can be performed. The immunoglobulin E (IgE)-mediated mechanism does not explain completely the severity and the clinical course of chronic allergic ocular diseases such as vernal (VKC) and atopic keratoconjunctivitis (AKC), which are probably also related to T cell-mediated responses, massive eosinophil attraction and activation and non-specific hypersensitivity. An altered balance between T helper type 1 (Th1) and Th2 cells and between Th1- and Th2-types of cytokines is thought to be responsible of the development of ocular allergic disorders. New findings suggest that a wide range of cytokines, chemokines, proteases and growth factors are involved by complex interwoven interactions rather than distinct and parallel pathways. In addition, several non-specific enzymatic systems may be activated during acute and chronic allergic inflammation, thus contributing to the complex pathogenesis of the disease. Current drug treatment for ocular allergy targets the key mechanisms involved in the development of clinical disease: mast cells with mast cell stabilizers, histamine with histamine receptor antagonists and inflammation with corticosteroids, severe inflammation with immunomodulators. None of these agents lacks side effects and none abolishes signs and symptoms completely. New therapeutic strategies are still needed to respond to the complex pathogenesis of severe forms of ocular allergy such as VKC and AKC.

Obstructive sleep apnoea is improved by a prolonged treatment of gastrooesophageal reflux with omeprazole.

BACKGROUND: Obstructive sleep apnoea has been demonstrated to induce gastrooesophageal reflux through highly negative intrathoracic pressure during the attacks. However, we believe that gastrooesophageal reflux on its part may favour or aggravate the apnoea attacks. AIMS: We investigated whether the treatment of gastrooesophageal reflux with omeprazole is able to decrease apnoea attacks. PATIENTS AND METHODS: Twenty patients (mean age 55.4 years, range 49-73 years; 17 males) with confirmed obstructive sleep apnoea at overnight polysomnography and pathological gastrooesophageal reflux at ambulatory 24-h oesophageal pHmetry were asked to note in a diary the occurrence of apnoea attacks for a basal period of 4 weeks. Subsequently, the patients were randomly and in a double-blind manner treated with omeprazole 20mg (10 patients, group A) or placebo (10 patients, group B) by giving 1 cp 30 min before breakfast and 1 cp 30 min before dinner for another 6 weeks with a diary documentation. The results were averaged weekly and over the entire treatment duration and a statistical comparison was made between the groups and within each group before and after treatment. RESULTS: The mean weekly frequency of apnoea attacks of group A during the entire period of treatment with omeprazole was significantly decreased with respect to the basal period and was significantly lower than that of group B. The weekly frequency of apnoea attacks in group A started to be significantly lower from the third week than the corresponding values of both group B and the basal period, reaching a decrease of about 73% in the sixth week. CONCLUSION: The occurrence of apnoea attacks progressively decreased during the treatment of gastrooesophageal reflux with omeprazole. This fact suggests that gastrooesophageal reflux may play a role in triggering and/or worsening obstructive sleep apnoea.

A novel antireflux device based on magnets.

BACKGROUND: The problem of eliminating gastroesophageal reflux (GER) with simple, effective and devoid of unpleasant side effects procedures is still unresolved. We tried to settle this problem with a magnetic device that should be applied to the distal end of the esophagus. MATERIALS AND METHODS: Two plastoferrite magnets of 2 x 4 x 0.5cm(1) were applied, on the opposite sides of a flaccid polyethylene tube mimicking the physical characteristics of the terminal esophagus. The two magnets attracting themselves compressed the tube, creating an artificial high-pressure zone that divided the tube in two segments. Both segments of the tube were connected to pressure transducers and a polygraph and one of them was connected to a hydraulic pump. The pressure was progressively increased in this segment up to a value sufficient to detach the magnets with consequent flowing of the water in the other segment of the tube. RESULTS: The progressive increase of the pressure in a segment of the tube detached the magnets allowing a free flow into the other segment when the pressure reached an average value of 9.75+/-1.05 mmHg (mean+/-SD). CONCLUSIONS: A couple of magnets clamping a tube with the characteristics of the distal esophagus is able to prevent the passage of liquid with a pressure value near to that of a normal lower esophageal sphincter. This magnetic device could be useful to maintain closed a sphincter unable to prevent gastroesophageal reflux.

Molecular connectivity methods for the characterization of surface energetics of liquids and polymers.

In the topological approach to structure-property relationships, the molecular structure is described in terms of appropriate weighted graphs to which suitable topological parameters, usually known as molecular connectivity indices, can be associated. Molecular connectivity indices are here applied to the prediction of surface free energy and Good-van Oss-Chaudhury acid-base components of organic compounds. To this aim, some quantitative structure-property relationships (QSPRs) are determined, involving both topological indices and group indicator variables of the customary functional group theory. The semiempirical models obtained to appear satisfactory and show significant advantages with respect to the models based on the purely functional group approach.

CD38 as a target of IB4 mAb carrying saporin-S6: design of an immunotoxin for ex vivo depletion of hematological CD38+ neoplasia.

An anti-CD38 mAb (IB4) coupled to saporin-S6, a type 1 ribosome-inactivating protein (RIP), was designed for ex vivo or loco-regional therapeutical applications in myeloma and lymphoma. The ability of this immunotoxin to eliminate CD38+ cells was studied in vitro on selected CD38+ human cell lines (Raji, HBL6, L540 and CEM) and on CD38+ neoplastic cells from a Non Hodgkin Lymphoma (NHL) patient. HBL6, Raji and L540 cells resulted very sensitive to the IB4/saporin-S6 conjugate, concentrations as low as 100 pM of the immunotoxin completely inhibited protein synthesis. CD38+ neoplastic cells from the NHL patient were completely eliminated after treatment with immunotoxin at 10 nM concentration. CFU-c rescue by bone marrow precursors was maintained after exposure to the immunotoxin. These results indicate that IB4/saporin-S6 is endowed with strong and specific cytotoxic effects on selected CD38+ tumor cells lineages. Consequently, it is reasonable to propose a clinical use of the IB4/saporin-S6 for ex vivo purging of unwanted cells (e.g. depletion of contaminating neoplastic cells in aphereses obtained from G-CSF-treated patients) or for loco-regional therapies of CD38+ tumors.

The treatment of functional dyspepsia with red pepper.

AIM: : To decrease the intensity of dyspeptic symptoms by impairing the visceral nociceptive C-type fibres with capsaicin, contained in red pepper powder. METHODS: : The study was performed on 30 patients with functional dyspepsia and without gastro-oesophageal reflux disease and irritable bowel syndrome. After a 2-week washout period, 15 patients received, before meals randomly and in a double-blind manner, 2.5 g/day of red pepper powder for 5 weeks, and 15 patients received placebo. A diary sheet was given to each patient to record, each day, the scores of individual and overall symptom intensity, which subsequently were averaged weekly and over the entire treatment duration. RESULTS: : The overall symptom score and the epigastric pain, fullness and nausea scores of the red pepper group were significantly lower than those of the placebo group, starting from the third week of treatment. The decrease reached about 60% at the end of treatment in the red pepper group, whilst placebo scores decreased by less than 30%. CONCLUSIONS: : Red pepper was more effective than placebo in decreasing the intensity of dyspeptic symptoms, probably through a desensitization of gastric nociceptive C-fibres induced by its content of capsaicin. It could represent a potential therapy for functional dyspepsia.

Sildenafil inhibits gastroduodenal motility.

BACKGROUND: Sildenafil shows an intense and prolonged inhibitory effect on the smooth muscle cells of corpus cavernosum arterioles by blocking phosphodiesterase-type 5, which inactivates the nitric oxide-stimulated cyclic guanosine monophosphate. AIM: To investigate whether this inhibitory effect is also displayed on the musculature of the gastroduodenal tract. METHODS: In 16 normal subjects, antroduodenal motility was recorded by means of a low-compliance manometric system. Ten minutes after the appearance of a phase III of the migrating motor complex, a tablet of sildenafil 50 mg, dissolved in 20 mL of water, was infused in the gut of eight patients, or a placebo in the other eight patients, randomly and in a double-blind manner, continuing the recording for 90 min. The frequency and amplitude of antral and duodenal waves, measured during the first 60 min after infusion in the two groups, were compared statistically. In addition, the duration of antral and duodenal phases I, and the number of phases III occurring during the whole 90 min after infusion, were compared in the two groups. RESULTS: Antral and duodenal wave frequency and amplitude were significantly lower during the first 60 min after sildenafil administration. Both antral and duodenal phases I were significantly longer after sildenafil than after placebo, and the number of phases III which occurred during the 90 min after sildenafil was significantly lower than after placebo. CONCLUSIONS: Sildenafil inhibits interdigestive motor activity of the antrum and duodenum.

Effects of oral clarithromycin and amoxycillin on interdigestive gastrointestinal motility of patients with functional dyspepsia and Helicobacter pylori gastritis.

BACKGROUND: Clarithromycin and amoxycillin are antibiotics commonly used in association for Helicobacter pylori eradication. Because this treatment, which lasts 1-2 weeks, is frequently associated with gastrointestinal symptoms, we investigated the effects of these antibiotics on gastrointestinal motility. PATIENTS AND METHODS: Gastroduodenal motility was recorded in 14 patients with functional dyspepsia and H. pylori gastritis by means of a low-compliance manometric system with four recording ports in the stomach and four in the duodenum. Two tablets of clarithromycin 250 mg (seven patients, clarithromycin group) or one of amoxycillin 1 g (seven patients, amoxycillin group), ground and dissolved in 20 mL of water, were given randomly and in double-blind manner 30 min after the end of the first activity front (AF) of the migrating motor complex (MMC) or, in the absence of AFs, after at least 200 min of recording. Recording continued until an AF was observed during the subsequent 200 min. RESULTS: Clarithromycin administration was followed by a typical gastroduodenal AF in a significantly higher number of patients than for amoxycillin administration. In addition, the time lag between clarithromycin administration and the appearance of AFs was 48 min +/- 8.5 (mean +/- s.d.), significantly shorter than after amoxycillin (121 min +/- 29). The clarithromycin-related duodenal AFs showed a duration of 6.6 min +/- 1.5, significantly longer than that of the spontaneous AFs (3.6 min +/- 1.2, P < 0.01), while the amoxycillin-related AFs were not significantly different from the spontaneous ones. CONCLUSION: Clarithromycin stimulated cyclic gastroduodenal motility, while amoxycillin was ineffective. It is likely that symptoms during the eradication treatment are due to this effect of clarithromycin.

Dilated intercellular spaces as a marker of oesophageal damage: comparative results in gastro-oesophageal reflux disease with or without bile reflux.

BACKGROUND: The dilation of oesophageal intercellular spaces, clearly apparent in transmission electron microscopy images, is a marker of cellular damage induced by acid. AIM: To analyse the presence of dilated intercellular spaces and to quantify the scores in controls and in patients with gastro-oesophageal reflux disease or duodenal gastro-oesophageal reflux accompanied by erosive or non-erosive reflux disease. METHODS: Thirty-eight symptomatic patients with gastro-oesophageal reflux disease or duodenal gastro-oesophageal reflux and 12 asymptomatic controls, classified on the basis of pH-metry and bilimetry, underwent endoscopy. Six tissue biopsies were taken from the normal mucosa for light microscopy and transmission electron microscopy evaluation. Dilated intercellular spaces were measured on photomicrographs of the specimens (at least 100 transects were measured for each patient). RESULTS: Twenty-two patients with gastro-oesophageal reflux disease had normal macroscopic mucosa but, at histology, five patients with erosive gastro-oesophageal reflux disease had mild oesophagitis and one had moderate oesophagitis. Seven patients with duodenal gastro-oesophageal reflux had normal mucosa, whilst three with erosive duodenal gastro-oesophageal reflux had mild oesophagitis at histology. At transmission electron microscopy, all controls had dilated intercellular spaces of less than 1.69 microm. Each symptomatic patient had a mean dilated intercellular space value and a mean value of the maximum dilated intercellular space at least three or more times greater than that in controls (P < 0.001). No statistical differences were observed between erosive and non-erosive oesophagitis. CONCLUSIONS: The dilated intercellular space is an extremely sensitive marker of damage in gastro-oesophageal reflux disease, duodenal gastro-oesophageal reflux and non-erosive reflux disease, and serves as the most appropriate marker of damage evaluation in non-erosive reflux disease reported to date. A mean dilated intercellular space of 0.74 micro m provides a cut-off score for damage. No quantitative or qualitative differences in dilated intercellular space scores were found between pure and mixed acid reflux.

Twenty-four hour ambulatory antroduodenal manometry in normal subjects (co-operative study).

Circadian antroduodenal motor activity was studied in 40 normal subjects by means of a portable recording system consisting of a computerized data logger and a probe with microtransducers. The quantitative and qualitative characteristics of contraction events during the interdigestive and digestive periods, as well as during the awake and asleep periods, were analysed. The composition and timing of meals and night recumbence were standardized. In spite of the high interindividual variability in motor parameters, significant differences in the characteristics of interdigestive and digestive periods between waking and sleep states were found. This paper confirms the existence of a circadian variation in antroduodenal motor activity and provides reference values from a large series of normal subjects that can be used for statistical comparisons with those obtained from patients recorded with the same method.

Brain stem encephalitis in a patient with gastroduodenal and cardiovascular dysfunction: a case report.

The authors describe a case of a 38-year-old woman suffering from long-standing epigastric pain, abdominal fullness and vomiting due to functional alteration of gastroduodenal motility. Following a surgical procedure, a supraventricular tachyarrhythmia and hemodynamic disturbances suddenly appeared and led to death in a few hours. A histopathological study carried out on the brain stem revealed inflammatory lesions suggestive of a viral infection, whereas the study of the conduction system of the heart did not show any alterations. A clinicopathological correlation is suggested between the clinical picture and anatomical lesions of the tegmental region.

Relationship between acid secretory activity and gastroduodenal migrating motor complex.

BACKGROUND/AIMS: As acid secretory activity fluctuates with the same rhythm as motor activity during the interdigestive period, we investigated the relationship between these two cyclic activities. MATERIAL AND METHODS: In a series of 9 normal subjects the interdigestive gastroduodenal motor activity and the intragastric pH were recorded after an overnight fasting by means of a manometric and pH-metric apparatus. Thirty minutes after the second phase III of the Migrating Motor Complex (MMC), omeprazole, a proton pump inhibitor, was administered intravenously at a dose of 20 mg. RESULTS: After omeprazole administration, a typical gastroduodenal phase III similar to the spontaneous one appeared before its expected occurrence. The amplitude and frequency of pressure waves of the period between the end of omeprazole administration and the beginning of phase III were not significantly different from those of the period preceding the spontaneous phase III, but were significantly different from those of a corresponding period starting 30 min after a spontaneous phase III. The intragastric pH showed a significant increase from the basal values before the beginning of gastric phase III and continued to increase up to the end of recording. CONCLUSIONS: The fact that the block of gastric acid secretion is followed by the appearance of a typical gastroduodenal phase III suggests that the acid secretory activity may have some influence on motor activity of the gastroduodenal tract.