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Biomedical subjects

A De Stefano

Publications and source records attributed to A De Stefano.

At least 19 recordsLinked to original sources
PubMed2007

Breast cancer local recurrence: risk factors and prognostic relevance of early time to recurrence.

BACKGROUND: Local recurrence occurs in 10%-20% of patients treated with breast-conserving surgery for stage I-II breast cancer. The aim of the present study was to investigate breast cancer local recurrence, potential risk factors, and prognostic impact. METHODS: A total of 503 patients treated with breast-conserving surgery were included in the study. All patients underwent axillary dissection and postoperative radiotherapy, and all patients had negative margins at pathological examination. Median follow-up was 82 months. Local recurrence was classified as early when it occurred within 2 years from surgery. The risk factors for local recurrence and overall survival were estimated by univariate and multivariate analyses. RESULTS: Forty-six cases (9.1%) of local recurrence were observed, 11 of which occurred within 24 months of surgery; the other 35, sometime later. Statistically significant risk factors for local recurrence were premenopausal status, peritumoral vascular invasion, multifocality, and absence of estrogen receptors. Independent negative prognostic factors for overall survival at 5 and 10 years were N stage, absence of estrogen receptors, and early time to recurrence. Overall survival at 10 years was 10.0% for patients with early recurrence, 87.5% for patients with late recurrence, and 87.9% for patients without recurrence. CONCLUSIONS: None of the studied clinicopathological characteristics alone is a determinant for the choice of surgical treatment. Younger patients treated with breast-conserving surgery should receive aggressive postsurgical treatment and should be followed with an intensive follow-up program when metastatic axillary lymph nodes, negative estrogen receptors, or peritumoral vascular invasion are present.

Adult↗
PubMed2006

Hereditary diffuse gastric cancer and E-cadherin: description of the first germline mutation in an Italian family.

AIMS: Germline mutation of the E-cadherin gene (CDH1) accounts for the Hereditary Diffuse Gastric Cancer (HDGC) syndrome. Fourteen pedigrees with Diffuse Gastric Cancer that fulfilled the International Gastric Cancer Linkage Consortium (IGCLC) criteria were selected and screened for CDH1 germline mutations. METHODS: The entire coding region of the CDH1 gene and all intron-exon boundaries were analyzed by direct sequencing in the 14 families fulfilling the IGCLC criteria. E-cadherin immunohistochemical expression was evaluated on tumour as well as normal formalin-fixed paraffin embedded tissues. RESULTS: A novel germline missense mutation was found. It was a single C-->T substitution in exon 8, resulting in a transition of CCG-->CTG (C1118T; Pro373Leu) demonstrated in the proband and her brother. At immunohistochemical analysis, the staining intensity was reduced and considered weakly positive (15%). CONCLUSIONS: The first CDH1 germline mutation of an Italian family is herein reported. The present missense mutation has never been described so far.

Cadherins↗
PubMed2006

Pseudoaneurysm of the splenic artery fistulized in the stomach and associated to a pancreatic pseudocyst: case report.

A case of pseudoaneurysm of the splenic artery fistulized in the stomach and associated to a pancreatic pseudocyst is presented. A diabetic and alcoholist 40-year-old man was referred for gastrointestinal bleeding. Esophagogastro-duodenoscopy showed a tumefaction of the little gastric curve and a gastric bleeding fistula. A computed tomography demonstrated a pseudoaneurysm of the splenic artery fistulized in the stomach and associated to pancreatic pseudocyst. Marsupialization of the pancreatic pseudocyst, ligature of the splenic artery, splenectomy and closure of the gastric bleeding fistula were performed. There were no postoperative complications and the follow-up showed no other complications. Aneurysms and pseudoaneurysms of the splenic artery are very frequent, generally asymptomatic (70% of the cases) and in half of the cases they are occasionally diagnosticated. The bleeding of pseudoaneurysm for rupture or fistulization is a very rare and serious complication associated to a high percentage of mortality.

Journal Article↗
PubMed2005

A simulation model of the surface EMG signal for analysis of muscle activity during the gait cycle.

This work describes a model able to synthetize the surface EMG (electromyography) signal acquired from tibialis anterior and gastrocnemious medialis muscles during walking of asymptomatic adult subjects. The model assumes a muscle structure where the volume conductor is represented by multiple layers of anisotropic media. This model originates from analysis of the single fiber action potential characterized by the conduction velocity. The surface EMG of voluntary contraction is calculated by gathering motor unit action potentials estimated by the summation of all activities of muscle fibers assumed to have a uniformly parallel distribution. The parameters related to the gait cycle, such as onset and cessation timings of muscle activation, amplitude of muscle contraction, periods and sequences of motor units' recruitment, are included in the model presented. In addition, the relative positions of the electrodes during gait can also be specified in order to adapt the simulation to the different acquisition settings.

Computer Simulation↗
PubMed2005

Demystifying biomedical signals: a student centred approach to learning signal processing.

The processing and analysis of physiological signals has become firmly established in clinical medicine and biomedical research. Many of the users of this technology however do not come from an engineering or science background, and traditional approaches in teaching signal processing are thus not appropriate for them. We have therefore developed a series of modular courses that are aimed specifically at an audience with a background in medicine, health-care or the life-sciences. In these courses, we focus on the concepts, principles and rationale of applying signal processing methods, rather than the mathematical foundations of the techniques. Thus, we aim to remove some of the perceived 'mystery' often surrounding this subject. The very practical approach, with hands-on experience using the MATLAB software, has been well received, with strong evidence that students have learnt to apply their knowledge. This paper describes the learning and teaching approach taken, and some of the experience acquired.

Algorithms↗
PubMed2005

Pharmacokinetics of mitomycin C after resection of peritoneal carcinomatosis and intraperitoneal chemohyperthermic perfusion.

Over the last few years surgery on patients with abdominal malignancies has become more aggressive but the majority of patients present locoregional recurrence as peritoneal dissemination. Cytoreductive surgery followed by intraperitoneal chemohyperthermic perfusion (ICHP) has been described for treatment and prevention of locoregional cancer spread from various origins. This paper reports our study of the pharmacokinetics of mitomycin C (MMC) administered by intraperitoneal chemohyperthermic perfusion (ICHP) in patients with peritoneal carcinomatosis. 28 patients received MMC 20 mg/m2 intraperitoneally as a perfusion over 60 min. MMC was determined in perfusate, plasma and urine samples with a UV-HPLC method. A compartmental model was used to fit the drug concentrations in plasma and perfusate. Our results showed a mean maximum plasma concentration (Cmax) of 0.14 +/- 0.086 microg/ml with a peak time (Tmax) of 48..7 +/- 5.61 min. The mean area under the curve (AUC) and terminal half-life (t1/2) were 15.8 +/- 9.8 mg x min/L and 83.7 +/- 31.74 min respectively. Clearance (CL) was estimated by fitting the data by a compartmental model and the mean value was 72 +/- 66 L/h. The percent of the dose absorbed was very variable and ranged between 14 and 57% (mean 37 +/- 14%). The mean percentage of dose recovered unchanged in the urine during 24 hours was 7.21 +/- 3.73%. We conclude that ICHP in patients with peritoneal surface malignancies seems to have clinical value since it gives high peritoneal and tumor MMC concentrations with limited systemic exposure and toxicity.

Adult↗
PubMed2004

Noise reduction in spine videofluoroscopic images using the undecimated wavelet transform.

Videofluoroscopy permits using sequences of low quality images to study the spine movement. In this work the problem of enhancing the quality of these images is considered in order to facilitate the extraction of kinematic parameters. The method is based on the undecimated wavelet transform and on a preliminary training of a sub-set of images. The anatomical features are preserved using a mask. Key element of the method is its fast and automated implementation. The concept of improving the extraction of kinematic parameters by improving the image representation instead of the technique to extract these is also innovative. The technique has been tested on two sequences of images and the results demonstrates that the method enhances images not related with training sub-set.

Algorithms↗
PubMed2004

Factors influencing outcome in gastric cancer involving muscularis and subserosal layer.

AIMS: The prognostic factors for advanced gastric carcinoma without serosal invasion (pT2 AGC) are not clear. In terms of prognosis, pT2 AGC is considered intermediate between early gastric cancer (EGC) and gastric carcinoma with serosal invasion. METHODS: From January 1985 to December 2000, 182 patients with pT2 AGC underwent curative gastric resection in our Department. Prognostic factors were evaluated by univariate and multivariate analyses. RESULTS: Univariate analysis demonstrated that gender, tumour location, lymph node involvement, Borrmann type, number of lymph nodes involved, venous infiltration and extent of lymphadenectomy were significantly related to the prognosis. Multivariate analysis revealed that extent of lymph node metastasis (N1 vs N0 relative risk (RR) of recurrences=3.96, p<0.05; N2 vs N0 RR=6.55, p<0.05), and extent of lymphadenectomy (D1 vs D2 RR=3.2, p<0.01) were independent prognostic factors. In a subset of patients in which venous infiltration was analysed, this factor was also significant (RR=3.9, p<0.05). CONCLUSIONS: Our study shows that lymph node involvement and venous infiltration are important prognostic factors for pT2 AGC and, as such, adjuvant chemotherapy could be useful in this group of patients. An extensive lymph node dissection, minimum D2, should always be performed in order to reduce the risk of recurrence.

Adult↗
PubMed2004

Effect of gait cycle selection on EMG analysis during walking in adults and children with gait pathology.

This paper presents the results of a project to evaluate different methods of gait cycle selection on the analysis of electromyography recorded during gait. Electromyography (EMG) describes the electrical activity associated with the muscle and is often interpreted in gait analysis using a simultaneously obtained signal to identify phases of the gait cycle. Phase transitions are often selected manually from reference signals derived from additional instrumentation, such as pressure platforms, footswitches and video cameras. We propose two methods (automatic and semi-automatic) as an alternative to the more traditional manual selection, and analyse how the gait cycle selection affects the EMG analysis. To quantify the differences between the gait cycles obtained using each method and to classify each cycle, three indices have been introduced. The effect of the gait cycle selection has been evaluated with respect to the EMG step profiles and temporal gait descriptors. An asymptomatic adult, an asymptomatic child and two children with cerebral palsy were examined using telemetric EMG devices and pressure footswitches. The results obtained showed that the method of gait cycle selection did not have a major influence for the adult, but it altered considerably the analysis in the case of the children with cerebral palsy.

Adult↗
PubMed2003

Prospective study of peritoneal recurrence after curative surgery for gastric cancer.

BACKGROUND: Peritoneal carcinomatosis is a common cause of failure after surgery for gastric cancer. The present longitudinal study was designed to evaluate the incidence and potential predictors of peritoneal recurrence after curative resection for gastric cancer. METHODS: Four hundred and forty-one patients who underwent potentially curative resections for gastric cancer in three surgical centres between 1988 and 1996 were evaluated. All patients were followed using a standard protocol following discharge from hospital. The correlation between tumour recurrence and clinicopathological variables was studied by univariate and multivariate analyses. RESULTS: Gastric cancer recurred in 215 (49 per cent) of 441 patients. Peritoneal recurrence was observed in 77 patients (17 per cent), locoregional recurrence in 96 patients and haematogenous recurrence in 75. Multivariate logistic regression analysis of factors associated with peritoneal recurrence identified diffuse-mixed histological type (relative risk (RR) 4.31, P < 0.001), infiltration of the serosa (RR 3.36, P = 0.001), lymph node involvement (RR 2.67, P = 0.023) and tumour size (RR 1.11, P = 0.050) as significant independent variables. In the diffuse-mixed histological subtype, the 5-year cumulative risk of peritoneal recurrence was 12 per cent in the absence of serosal invasion, and 69 per cent in patients with infiltration of the serosa; in the intestinal subtype, the cumulative risk in patients with serosa-negative and -positive tumours was 4 and 21 per cent respectively. CONCLUSION: Radical surgery offers a low probability of cure in patients with diffuse-mixed type of gastric cancer and involvement of the serosa, due to a high risk of peritoneal recurrence. These patients might benefit from adjuvant therapies to prevent peritoneal carcinomatosis.

Adult↗
PubMed2001

Preoperative positivity of serum tumor markers is a strong predictor of hematogenous recurrence of gastric cancer.

BACKGROUND AND OBJECTIVES: Preoperative positivity of serum tumor markers has been reported to be a prognostic factor in several neoplasms. The aim of this longitudinal study was to evaluate the correlation between CEA, CA 19-9, and CA 72-4 preoperative serum levels and the site of recurrence after curative surgery for gastric cancer. METHODS: One hundred sixty-seven patients resected for primary gastric cancer between January 1988 and June 1996 were considered. All patients were followed-up according to the same protocol, with a mean follow-up time of 45 +/- 39 months (range: 2-130). The correlation between marker positivity and the incidence of recurrence was studied by means of univariate and multivariate analyses. RESULTS: A tumor recurrence was found in 92 patients (55.1%). For each of the three markers, preoperative positivity was related to a higher incidence of hematogenous recurrences with respect to negative cases; univariate analysis also revealed a higher incidence of locoregional recurrences in CA 72-4-positive cases. At multivariate analysis, preoperative positivity for one or more tumor markers proved to be an independent predictor of hematogenous recurrences (P < 0.005, relative risk [RR] 4.82), in addition to lymph node involvement (P < 0.05, RR 3.82); no correlation between marker positivity and the onset of locoregional or peritoneal recurrences was found. CONCLUSIONS: Preoperative positivity for CEA, CA 19-9 or CA 72-4 is an independent risk factor for hematogenous recurrences of gastric carcinoma; this aspect should be considered in the option of using adjuvant chemotherapy after surgery for gastric cancer.

Adult↗
PubMed2001

Clinical utility of CEA, CA 19-9, and CA 72-4 in the follow-up of patients with resectable gastric cancer.

BACKGROUND: The aim of this longitudinal study was to evaluate the effectiveness of the serum tumor markers CEA, CA 19-9, and CA 72-4 in the early diagnosis of recurrence of gastric cancer. METHODS: One hundred and thirty-three patients who had undergone potentially curative surgery were considered. Serum samples were obtained preoperatively, 1 week after surgery, and at every follow-up examination. Mean follow-up time for the entire patient population was 41 +/- 33 months, and 71 +/- 27 months for patients classified as disease-free. RESULTS: Preoperative positivity was 16% for CEA, 35% for CA 19-9, and 20% for CA 72-4. Recurrence of disease was found in 75 patients (56%). Marker sensitivity in recurrent cases was 44% for CEA, 56% for CA 19-9, and 51% for CA 72-4; the combined use of the three markers increased sensitivity to 87%, which reached 100% in patients with positive preoperative levels. Marker specificity, evaluated in 58 disease-free patients, was 79% for CEA, 74% for CA 19-9, and 97% for CA 72-4. CONCLUSIONS: The combined assay of CEA, CA 19-9, and CA 72-4 may be useful for early diagnosis of recurrence of gastric cancer; however, only CA 72-4 positivity should be considered a specific predictor of tumor recurrence.

Aged↗
PubMed2001

Endoscopic argon plasma coagulation for palliative treatment of malignant airway obstructions: early results in 47 cases.

Argon plasma coagulation (APC) is a new method of non-contact electrocoagulation, using high frequency current by means of ionized argon gas (argon plasma). Recently, this technique has become available for flexible endoscopic delivery through special probes. Aim of this study is to evaluate the efficacy, indications and the possible side effects of APC use in the palliative treatment of malignant airway obstructions and/or bleeding. Over a 24-month period, 47 patients underwent APC treatment for malignant neoplasms of the tracheobronchial system causing obstruction and/or recurrent bleeding. Immediate airway patency and haemostasis were obtained in 91.5% of cases (43/47). No complications or side effects caused by the treatment were observed. In two patients, the treatment allowed a radical surgical approach after induction chemotherapy. In all cases, APC proved to be highly effective and easy to perform. In our experience, APC has proven to be easy to perform, rapidly effective, safe and well tolerated by the patient, even after repeated application. This study highlights the value of endoscopic APC in the palliative management of tracheobronchial neoplasms.

Adult↗
PubMed2000

Surgical treatment of gastrointestinal carcinomas in octogenarians: risk factors for complications and long-term outcome.

BACKGROUND: The aims of this retrospective study were to determine the factors predictive of morbidity and mortality, and to evaluate the probability of long-term survival in octogenarians with carcinomas of the gastrointestinal tract. PATIENTS AND METHODS: Out of a total of 194 patients, aged 80 years or over, with histologically diagnosed carcinoma of the stomach or colon-rectum, observed between 1987 and 1995, 167 underwent surgery and were included in this study. The relationship between a series of clinico-pathological variables and morbidity/mortality rates was investigated by univariate and multivariate analysis. Complete follow-up data were available in 161 patients. RESULTS: Fifty-nine patients (35.3%) experienced complications and 14 (8.4%) died during hospitalization. Statistical analysis identified hypoalbuminaemia (P<0.01, relative risk (RR)=2.92) and hypercreatininaemia (P<0.05, RR=3.59) as independent predictors of post-operative complications. Hypercreatininaemia (P<0.05, RR=5.22) and non-curative surgery (P<0. 05, RR=3.99) significantly affected operative mortality. Crude 5-year survival rate, including operative mortality after curative surgery, was 41% in gastric cancer and 39% in colorectal cancer patients. CONCLUSION: These results indicate that surgery for gastrointestinal carcinomas yields an acceptable operative risk in octogenarians, and provides good long-term results if oncological radicality can be obtained. Pre-operative evaluation of tumour stage and patient's general condition is useful to identify subgroups of patients at high risk of surgical complications and mortality.

Aged↗
PubMed2000

[Trends in stomach carcinoma. A statistical analysis of 1204 cases].

The authors report a retrospective analysis of their experience of gastric cancer. One thousand two hundred and four patients, observed between 1977 and 1994, of whom 1,094 underwent surgery, were studied. Data analysis was performed, dividing this period as follows: 1977-1982, 1983-1988, 1989-1994. The results reveal that, over time, substantial changes occurred both in tumor characteristics and surgical approach. With regards to tumor characteristics, the disease weighs heavily, even if it is less frequent than in the past (25% reduction), striking younger subjects and presenting in increasingly more aggressive forms [higher frequency of proximal (+11.4%) and diffuse forms (+18.1%), reduction of advanced forms (-11.6%) not proportional to the increase of early forms (+64.5%), as well as increase of cases with a short clinical history (+15.2%)]. In terms of surgical approach, while the use of conservative surgery was reduced during the study period, extensive procedures were more widely used, particularly in the curative treatment of advanced tumors (subtotal gastrectomies: reduction of 39.5%; total gastrectomies: increase of 106%). The increasing use of extended surgery is linked to the modifications occurred in tumor characteristics and in pre and post-operative management rather then to changes in surgical approach. It must be noted, however, that such technical advances have not yielded an improvement in survival (p = n.s.); as such, it is likely that gastric cancer has became a more aggressive disease and, therefore, has counterbalanced the benefits of early diagnosis and extended exeresis.

Adolescent↗
PubMed1999

P53 accumulation is a prognostic factor in intestinal-type gastric carcinoma but not in the diffuse type.

BACKGROUND: The prognostic value of p53 nuclear accumulation in gastric cancer is still unclear, as shown by the discordant results still reported in the literature. In this study, we evaluated the correlation between p53 accumulation and long-term survival of patients resected for intestinal and diffuse-type gastric cancer. METHODS: Eighty-three patients with carcinoma of the intestinal type and 53 patients with carcinoma of the diffuse type were included in the study. Immunohistochemical staining of the paraffin sections was performed by using monoclonal antibody DO1; cases were considered positive when nuclear immunostaining was observed in 10% or more of the tumor cells. Prognostic significance of different variables was investigated by univariate and multivariate analysis. RESULTS: p53 positivity was found in 51.8% of intestinal-type and 50.9% of diffuse-type cases. No significant correlation between the rate of p53 overexpression and age, sex, tumor location, tumor size, depth of invasion, lymph node involvement, distant metastases, and surgical radicality was found in the two groups of patients. A statistically significant difference in survival rate was observed between p53-negative and p53-positive cases in the intestinal type (P < .05), confirmed by multivariate analysis (P < .005; relative risk = 3.09). On the contrary, no correlation with survival was found in diffuse-type cases according to p53 overexpression. CONCLUSIONS: These results suggest that the immunohistochemical detection of p53 accumulation is a useful indicator of poor prognosis in the intestinal but not in the diffuse type of gastric cancer, and are indicative of distinct molecular pathways and pattern of progression in the two histotypes.

Adult↗