Biomedical subjects

A Micheletti

Publications and source records attributed to A Micheletti.

At least 19 recordsLinked to original sources

PubMed2005

Role of atrial septostomy in the treatment of children with pulmonary arterial hypertension.

OBJECTIVES: To assess in retrospect the safety and effectiveness of atrial septostomy in children with severe pulmonary arterial hypertension without an intracardiac communication. METHODS: 20 patients were reviewed retrospectively, 19 with idiopathic pulmonary arterial hypertension. The mean age at septostomy was 8.4 years (range 3 months to 17 years). Graded balloon septostomy alone was carried out in eight patients, a blade septostomy was done in two, a blade septostomy plus graded balloon septostomy was done in three, and a fenestrated device was inserted in seven. RESULTS: There were no fatalities. Four children suffered complications during the procedure. None had further syncope and all improved symptomatically with a significant (p < 0.01) decrease in World Health Organization functional class (mean shift -0.6) and a significant improvement in the semiquantitative echocardiographic assessment of right ventricular function (p < 0.03). The mean oxygen saturation decreased by 7.8 percentage points. The atrial communication closed in two children, necessitating a repeat procedure. After a mean follow up of 2.1 years (range one month to 6.7 years), 18 of 20 children are still alive. CONCLUSION: Atrial septostomy improved symptoms and quality of life in a group of children deteriorating with severe pulmonary arterial hypertension. This procedure is to be recommended for severely symptomatic children, before they become critically ill. Fenestrated devices may help ensure indefinite patency of the atrial communication.

Adolescent↗

PubMed2005

Occurrence and risk factors for benign epithelial gastric polyps in atrophic body gastritis on diagnosis and follow-up.

BACKGROUND: Benign epithelial gastric polyps have been reported to be more common in atrophic body gastritis. The role of Helicobacter pylori infection in the induction of gastric atrophy is well-known. The development of hyperplastic polyps may be in relation to H. pylori infection. AIM: To investigate occurrence of benign epithelial gastric polyps in atrophic body gastritis patients at diagnosis and follow-up, and the role of H. pylori and other risk factors for the development of benign epithelial gastric polyps. METHODS: A total of 259 consecutive atrophic body gastritis patients included in a follow-up programme, of whom 202 were followed up for median period of 4 years (range: 2-11). At baseline and follow-up gastroscopies, the presence of benign epithelial gastric polyps was evaluated. Biopsies for histology were obtained from all detected benign epithelial gastric polyps. RESULTS: Frequency of benign epithelial gastric polyps in atrophic body gastritis patients were 4.6% at baseline and 5.9% at follow-up. About 91.7% were hyperplastic polyps. H. pylori infection was detected in 79.2% atrophic body gastritis patients with benign epithelial gastric polyps, and in 70.8% without benign epithelial gastric polyps. Smoking was more frequent among patients with benign epithelial gastric polyps [42% vs. 20%, OR 2.8 (95% CI: 1.2-6.9)]. CONCLUSIONS: Benign epithelial gastric polyps occur in about 5% of atrophic body gastritis patients, and the vast majority are hyperplastic polyps. Smoking habit, but not H. pylori infection, increases the risk for benign epithelial gastric polyps in atrophic body gastritis patients.

Adolescent↗

PubMed2001

CD40 ligation ablates the tolerogenic potential of lymphoid dendritic cells.

The outcome of dendritic cell (DC) presentation of P815AB, a tolerogenic tumor/self peptide, depends on a balance between the respective immunogenic and tolerogenic properties of myeloid (CD8 alpha(-)) and lymphoid (CD8 alpha(+)) DC. We have previously shown that CD8(-) DC can be primed by IL-12 to overcome inhibition by the CD8(+) subset and initiate immunogenic presentation in vivo when the two types of peptide-pulsed DC are cotransferred into recipient hosts. IFN-gamma enhances the inhibitory activity of CD8(+) DC on Ag presentation by the other subset, blocking the ability of IL-12-treated CD8(-) DC to overcome suppression. We report here that CD40 ligation on lymphoid DC ablated their inhibitory function on Ag presentation as well as IFN-gamma potentiation of the effect. CD40 modulation of IFN-gamma action on lymphoid DC involved a reduction in IFN-gamma R expression and tryptophan-degrading ability. This effect was accompanied in vitro by an impaired capacity of the CD40-modulated and IFN-gamma-treated DC to initiate T cell apoptosis. In vivo, not only did CD40 triggering on lymphoid DC abrogate their tolerogenic activity, but it also induced the potential for immunogenic presentation of P815AB. Importantly, a pattern similar to P815AB as well as CD40 modulation of lymphoid DC function were observed on testing reactivity to NRP, a synthetic peptide mimotope recognized by diabetogenic CD8(+) T cells in nonobese diabetic mice.

Animals↗

PubMed2001

Zinc status in athletes: relation to diet and exercise.

Zinc is involved in the biochemical processes supporting life, such as cellular respiration, DNA reproduction, maintenance of cell membrane integrity and free radical scavenging. Zinc is required for the activity of more than 300 enzymes, covering all 6 classes of enzyme activity. Zinc binding sites in proteins are often of distorted tetrahedral or trigonal bipyramidal geometry, made up of the sulphur of cysteine, the nitrogen of histidine or the oxygen of aspartate and glutamate, or a combination. Zinc in proteins can either participate directly in chemical catalysis or be important for maintaining protein structure and stability. The nutritional habits of elite athletes during training and competition are quite different from the recommended diet in the majority of the population. Endurance athletes often adopt an unusual diet in an attempt to enhance performance: an excessive increase in carbohydrates and low intake of proteins and fat may lead to suboptimal zinc intake in 90% of athletes. Mild zinc deficiency is difficult to detect because of the lack of definitive indicators of zinc status. In athletes, zinc deficiency can lead to anorexia, significant loss in bodyweight, latent fatigue with decreased endurance and a risk of osteoporosis.

Absorption↗

PubMed2001

Physical exercise intensity can be related to plasma glutathione levels.

The aim of the present study was to examine the effect of different kinds of physical exercise on plasma glutathione levels. Male Wistar rats were randomly divided into four groups: In walking group (W; n=6), rats were trained to walk 0.8 m/min for 45 min; slow running group (SR; n=6) were trained to run 4 m/min for 45 min; fast running group (FR; n=6) ran 8 m/min for 60 min and control rats (C; n=6) remained in their home cages. All animals were sacrificed after exercise and the levels of reduced glutathione (GSH) in plasma samples determined by high performance liquid chromatography (HPLC) with a fluorescent detector. Compared to controls, exercise did not change GSH plasma levels of the W group. A tendency to decrease blood GSH was observed in plasma samples of the SR group and in the FR group, physical exercise resulted in a dramatic decrease in GSH plasma levels. These data suggest that during light physical exercise there is a low production of reactive oxygen species (ROS) with a low request for antioxidant defence such as oxidation of GSH. The dramatic decrease observed in GSH levels in FR rats would indicate the presence of oxidative stress able to modify blood antioxidant profiles. Our results suggest that GSH plays a central antioxidant role in blood during intensive physical exercise and that its modifications are closely related to exercise intensity.

Animals↗

PubMed2001

Physical exercise intensity can be related to plasma glutathione levels.

The aim of the present study was to examine the effect of different kinds of physical exercise on plasma glutathione levels. Male Wistar rats were randomly divided into four groups: In walking group (W; n=6), rats were trained to walk 0.8 m/min for 45 min; slow running group (SR; n=6) were trained to run 4 m/min for 45 min; fast running group (FR; n=6) ran 8m/min for 60 min and control rats (C; n=6) remained in their home cages. All animals were sacrificed after exercise and the levels of reduced glutathione (GSH) in plasma samples determined by high performance liquid chromatography (HPLC) with a fluorescent detector. Compared to controls, exercise did not change GSH plasma levels of the W group. A tendency to decrease blood GSH was observed in plasma samples of the SR group and in the FR group, physical exercise resulted in a dramatic decrease in GSH plasma levels. These data suggest that during light physical exercise there is a low production of reactive oxygen species (ROS) with a low request for antioxidant defence such as oxidation of GSH. The dramatic decrease observed in GSH levels in FR rats would indicate the presence of oxidative stress able to modify blood antioxidant profiles. Our results suggest that GSH plays a central antioxidant role in blood during intensive physical exercise and that its modifications are closely related to exercise intensity.

Animals↗

PubMed2000

N-acetylcysteine increases apoptosis induced by H(2)O(2) and mo-antiFas triggering in a 3DO hybridoma cell line.

N-Acetylcysteine (NAC) has been used as an antioxidant to prevent apoptosis triggered by different stimuli in different cell types. It is common opinion that cellular redox, which is largely determined by the ratio of oxidized and reduced glutathione (GSH), plays a significant role in the propensity of cells to undergo apoptosis. However, there are also contrasting opinions stating that intracellular GSH depletion or supplemented GSH alone are not sufficient to lead cells to apoptosis or conversely protect them. Unexpectedly, this study shows that NAC, even if it maintains the peculiar characteristics of an agent capable of reducing cell proliferation and increasing intracellular GSH content, increases apoptosis induced by H(2)O(2) treatment and mo-antiFas triggering in a 3DO cell line. We found that 24 h of NAC pre-treatment can shift cellular death from necrotic to apoptotic and determine an early expression of FasL in a 3DO cell line treated with H(2)O(2).

Acetylcysteine↗

PubMed1999

Stereological analysis and modelling of gradient structures

Gradient structures are inhomogeneous along a particular gradient direction but homogeneous perpendicular to that direction. Consequently, structural parameters such as volume fraction or surface area density are local characteristics which depend on the 'vertical' coordinate with respect to the 'vertical' gradient axis. Analogously, models for gradient structures have model parameters depending on the vertical coordinate z. For example, a Voronoi tessellation with a gradient is generated by a gradient point process with a local intensity which is a function of z. Similarly, a gradient germ grain model is obtained from a gradient point process where the grain size distribution may also depend on z. For a gradient Boolean model, local volume fraction VV(z) and local surface area density SV(z) can be calculated from the model parameters. Stereological methods for gradient structures are based on vertical sections parallel to the gradient direction. Estimation of VV(z), SV(z) and local length density LV(z) is done by lineal analysis using horizontal test lines with vertical coordinate z. Similarly, lineal analysis is used to estimate local mean cell volume of gradient tessellations. For the estimation of local particle number density and size in the spirit of the Wicksell problem the use of kernel methods and distributional assumptions is required.

Journal Article↗

PubMed1997

High-performance liquid chromatographic determination of orotic acid as its methyl derivative in human urine.

Described is a method for the determination of orotic acid as its methyl ester in human urine. The method involves the use of solid-phase extraction to isolate pyrimidines from urine and derivatization with methanol and sulfuric acid, followed by isocratic high-performance liquid chromatography on a reversed-phase C18 column with UV absorbance detection. The assay is shown to be sufficiently sensitive for use in clinical investigations where elevated orotic acid excretion is suspected.

Adult↗

PubMed1996

Activated pyrolytic carbon tip pacing leads: an alternative to steroid-eluting pacing leads?

Pyrolytic carbon technology is known for its excellent mechanical properties and electrical conductivity; it is particularly biocompatible and does not require high production costs. The Sorin S100/4 lead is a ventricular passive fixation lead with a hemispherical electrode surface area of 4 mm2; the stimulating tip is made of a graphite core coated by a thin activated pyrolytic carbon layer. We evaluated the acute and medium-term performance of the unipolar version of this lead in 65 patients. At implantation, pacing threshold (at 0.5 ms) was 0.26 +/- 0.08 V; pacing impedance (at 5 V and 0.5 ms) was 537 +/- 94 omega and R wave amplitude was 15.0 +/- 5.5 mV. No lead related complications (dislodgment, perforation, exit block, etc.) occurred in any patient; one patient presented with a wire fracture after 26 months, due to subclavian crush syndrome. Follow-up procedures were performed at 1 week, and 2-, 10-, 18-, and 30-months postimplant. Since the leads were connected to pacemakers from different manufacturers, either voltage or duration thresholds were measured. In approximately two thirds of the patients, with an output of 2.5 V, a mean duration threshold of 0.16 +/- 0.13 ms at 1 week, 0.12 +/- 0.08 ms at 2 months, 0.11 +/- 0.06 ms at 10 months, 0.09 +/- 0.06 ms at 18 months, and 0.07 +/- 0.03 ms at 30 months, was measured. In the remaining one-third of the patients, a comparable voltage threshold trend was measured. The mean pacing impedance showed a transient drop at 1 week, and then increased to a plateau of about 600 omega reached after 10 months. No sensing defect occurred in any patient. Our data show good acute and intermediate-term results of the S100/4 lead; the early rise in threshold was remarkably blunted. Activated pyrolytic carbon tip leads might therefore be considered as a possible, inexpensive alternative to steroid-eluting leads.

Aged↗

PubMed1995

Endoscopic manometry of the sphincter of Oddi: its usefulness for the diagnosis and treatment of benign papillary stenosis.

BACKGROUND: Endoscopic manometry is considered useful to identify dysfunction of the sphincter of Oddi (SO) and to predict in which patients good results can be expected after endoscopic sphincterotomy, but this has not been definitively demonstrated. METHODS: Endoscopic manometry of the SO was used in a group of 30 patients with benign papillary stenosis (BPS), in comparison with 30 control subjects. During endoscopic manometry an intravenous bolus of cholecystokinin octapeptide was given to 12 patients and to 10 controls. In 24 BPS patients endoscopic sphincterotomy was performed. RESULTS: No significant differences were observed between controls and patients with regard to median values of SO basal (20 and 21.5 mmHg) and peak pressure (123 and 126 mmHg), wave amplitude (100 mmHg), frequency (4 waves/min), and propagation of the common bile duct/duodenum gradient (12.5 and 12.1 mmHg). In two BPS patients a paradoxic response to CCK-OP was observed. Endoscopic sphincterotomy, performed in 24 BPS patients (17 with SO basal pressure less than 40 mmHg and 7 with more than 40 mmHg), gave good results in 23, without any complication. No differences were observed in the results of the endoscopic sphincterotomy among patients with basal pressure more than 40 mmHg and those with less than 40 mmHg. CONCLUSIONS: On the basis of this study, manometric data do not seem helpful for diagnosis of BPS or to discriminate which patients can be treated with endoscopic sphincterotomy.

Case-Control Studies↗

PubMed1992

[Bilateral breast tumors].

From a retrospective analysis of 181 cases observed in a ten-year period (1980-1990), the authors registered a frequency of bilateral breast cancer comparable to that reported in the literature (1-12%). Early diagnosis is the only factor able to modify positively the prognosis, through an accurate follow up, based on blood and X-ray tests (low-density mammography).

Breast Neoplasms↗

PubMed1991

Selenium therapy in patients with precancerous and malignant oral cavity lesions: preliminary results.

Baseline selenium (Se) levels in serum samples were collected from 22 patients with precancerous and 19 with malignant oral cavity lesions as well as from 13 healthy controls of the same geographic areas. Mean serum Se levels were 105, 101, and 77.03 ng/ml in the precancerous, controls, and malignancy groups, respectively. A statistically significant difference (p less than 0.005) was found between the neoplastic and both the precancerous and control groups. After careful clinical evaluation, precancerous patients received three 4-week cycles of Se, in either inorganic or organic form. Of the 22 precancerous patients entering the study, 18 were available for evaluation of clinical response. The analysis of serum Se variations revealed that serum Se levels tended to increase after the first and second cycles and then gradually returned to baseline values. At the end of the therapy, there were two complete responses (CR), five partial responses (PR), six minor responses (MR), and five stable diseases (SD) with an objective response (CR + PR) of 38.8%. Progression after suspension of therapy occurred in 7 of 18 patients; this may indicate the need of a longer treatment period with this essential trace element.

Adult↗

PubMedDate not supplied

[New trends in the diagnosis of Crohn's disease].

The Authors in reviewing the diagnostic techniques commonly used in Crohn's disease, focus their attention on Indium-111 scanning. The method seems useful, not only to point out the complications of the disease (stenosis, abscess, fistula) but especially for the follow up of patients after surgery with early diagnosis of a possible relapse.

Crohn Disease↗

PubMedDate not supplied

[Peroperative endoscopic papillotomy in a patient with an abdominal aortic aneurysm and biliary calculi].

The authors report a case of abdominal aortic aneurysm associated with biliary tract lithiasis. The need to simultaneously treat both diseases is stressed. A technique which involves endoscopy during open surgery in order to prevent contamination is illustrated. The technique used together with other manoeuvres is part of a methodology aiming to broaden indications to the treatment of abdominal diseases associated with vascular diseases, limiting at the same time the risks of prosthetic infection.

Aged↗

PubMedDate not supplied

[Extracorporeal lithotripsy and endoscopy in the treatment of pancreatic lithiasis].

The decompression of the pancreatic duct with the extraction of stones by endoscopy is now recognized as an effective method for the treatment of some forms of chronic pancreatitis. The limits of this methodology are strictly linked to the morphology of the pancreatic duct and/or to the size, morphology and number of stones. The association of endoscopy with the ESWL often allows to overcome these limits. A case of lithiasis of the Wirsung in a patient affected by C.P. successfully treated associating endoscopy to ESWL is reported.

Adult↗

PubMedDate not supplied

[The use of scintigraphy with labelled leukocytes: our experience].

The authors describe various applications of scintigraphy with labeled leukocytes and its value in the diagnosis of gut diseases such as Crohn's disease, ulcerative colitis and related complications. Furthermore, the study of vascular prosthesis infection, cryptogenetic fever and abdominal sepsis, three cases of which are herein reported, is facilitated. The method, in conjunction with endoscopy and traditional radiology, revealed to be of great value in terms of sensitivity and specificity for the diagnosis of the aforementioned diseases. Therefore, the use of such method is encouraged in all those cases of abdominal sepsis of uncertain interpretation and in the evaluation of vascular prosthesis infection.

Adult↗

PubMedDate not supplied

[Anterograde laparoscopic cholecystectomy: when and why].

Today largely diffused is the concept that laparoscopic cholecystectomy (LC) represents the treatment of choice for symptomatic gallstones. Nonetheless some questions have been raised on the real safety of this new method in terms of procedure-related complications. On the basis of our experience with traditional open cholecystectomy, we have recently performed a prograde LC in those cases with difficulties in identifying the anatomical structures of the so called Calot's triangle. This alternative route can be easily performed laparoscopically and has been useful in reducing the time of the intervention in the most difficult setting and to increase the safety of the procedure. The technical details and the results are compared with those of the laparoscopic retrograde route.

Cholecystectomy, Laparoscopic↗