PubMed Health⌕ Search

Biomedical subjects

M Poggio

Publications and source records attributed to M Poggio.

At least 19 recordsLinked to original sources
PubMed2005

Reassessing the current TNM lymph node staging for renal cell carcinoma.

OBJECTIVE: The most commonly used staging system for renal cell carcinoma (RCC) is the tumor-node-metastasis (TNM) system. In the most recent TNM edition, lymph node (LN) involvement is defined as pN0, pN1, or pN2, depending on the number of metastatic LNs (none, 1, or >1). This study evaluated the prognostic value of this classification and tried to improve its clinical impact by considering an additional parameter, that is, LN density (ratio between number of positive LNs and total number of LNs retrieved). METHODS: All pathologic reports of radical nephrectomies performed for RCC in two urologic centers between November 1983 and December 1999 were reviewed. For each patient, complete clinical and pathologic data, number of LNs removed, location and number of positive LNs, and LN density were recorded. The Kaplan-Meyer method and the log-rank test were used to calculate cause-specific survival rates and to compare survival curves, respectively. RESULTS: A total of 735 patients underwent radical nephrectomy. Lymphadenectomy was performed in 618 cases, and the rate of positive LNs was 14.2%. The 5-yr cause-specific survival rate of pN+ patients was 18%, with no statistically significant difference between pN1 and pN2. The average number of LNs removed was 13 (range, 1-35). The median number of LNs involved was 3 (range, 1-18). LN density ranged between 3.7% and 100% (median, 22.9%). The number of LNs removed had no impact on survival in pN+ patients. The only significant unfavorable prognostic factors were >4 LNs involved (p = 0.02) and LN density >60% (p = 0.01). CONCLUSION: The results show that in RCC the current TNM stratification of positive LNs is not significantly correlated with prognosis. From our data it appears that classification as < or =4 or >4 LNs involved, supported by LN density, better reflects the impact of the disease on survival.

Adult↗
PubMed2005

Antiferromagnetic s-d exchange coupling in GaMnAs.

Measurements of coherent electron spin dynamics in Ga1-xMnxAs/Al0.4Ga0.6As quantum wells with 0.0006%<x<0.03% show an antiferromagnetic (negative) exchange between s-like conduction band electrons and electrons localized in the d shell of the Mn2+ impurities. The magnitude of the s-d exchange parameter, N0alpha, varies as a function of well width indicative of a large and negative contribution due to kinetic exchange. In the limit of no quantum confinement, N0alpha extrapolates to -0.09+/-0.03 eV indicating that antiferromagnetic s-d exchange is a bulk property of GaMnAs. Measurements of the polarization-resolved photoluminescence show strong discrepancy from a simple model of the exchange enhanced Zeeman splitting, indicative of additional complexity in the exchange split valence band.

Journal Article↗
PubMed2004

Prognostic value of the involvement of the urinary collecting system in renal cell carcinoma.

OBJECTIVES: The prognostic role of the invasion of the urinary collecting system (UCS) by renal cell carcinoma (RCC) has not attracted a notable amount of attention. The aim of this study was to investigate incidence and prognostic value of UCS involvement in RCC. MATERIAL AND METHODS: All pathological reports of radical nephrectomies performed in two centres of urology from November 1983 to December 1999 were reviewed in order to evaluate the invasion of the UCS (calices, renal pelvis, ureter). Patients were divided into two groups according to presence (Group 1) or absence (Group 2) of UCS invasion. The stage was determined according to the TNM 6th edition. Overall and cause-specific survival rates were evaluated. Univariate and multivariate analyses were performed. RESULTS: The evaluable specimens were 671 from the 735 examined; in 64 cases it was not possible to ascertain or to exclude UCS involvement. Invasion of the UCS was found in 59 cases (8.8%). Median follow-up was 59.0 months (range 0-216). Tumours invading the UCS were usually symptomatic, with high nuclear grade and predominantly high stage. At univariate analysis the 5 year overall and cause-specific survival rates of tumours invading the UCS were significantly lower when compared to those without UCS invasion (42.8% versus 60.8% and 45.5% versus 64.7%, respectively). When groups were stratified, according to the pT category, the 5-year cause-specific survival rate was only significantly different for the pT2 category (33.3% versus 76.9%). At the multivariate analysis TNM staging, symptoms at diagnosis and tumour grade were the only independent prognostic factors. CONCLUSION: The invasion of the UCS by RCC is unusual, particularly in small tumours. UCS involvement does not represent an independent prognostic factor. However, in organ-confined tumours (i.e. pT2) UCS involvement has an influence on the prognosis and should be taken into account when planning adjuvant treatments and follow-up.

Adult↗
PubMed2003

Local manipulation of nuclear spin in a semiconductor quantum well.

The shaping of nuclear spin polarization profiles and the induction of nuclear resonances are demonstrated within a parabolic quantum well using an externally applied gate voltage. Voltage control of the electron and hole wave functions results in nanometer-scale sheets of polarized nuclei positioned along the growth direction of the well. Applying rf voltages across the gates induces resonant spin transitions of selected isotopes. This depolarizing effect depends strongly on the separation of electrons and holes, suggesting that a highly localized mechanism accounts for the observed behavior.

Journal Article↗
PubMed2003

The number of lymph nodes examined and staging accuracy in renal cell carcinoma.

OBJECTIVE: To determine the number of lymph nodes that need to be examined to accurately stage the pN variable in patients undergoing radical nephrectomy (RN) for renal cell carcinoma (RCC). PATIENTS AND METHODS: We reviewed the operative and pathology reports of 725 patients with RCC submitted for RN. All tumours were classified using the fifth edition of the Tumour-Nodes-Metastasis classification. For each patient the number of lymph nodes removed was recorded. The patients were divided into five different groups according to the number of nodes removed, i.e. group 1, 1-4; group 2, 5-8; group 3, 9-12; group 4, 13-16; and group 5, >or= 17. We evaluated the factors that affected the number of lymph nodes removed with nodal dissection and the variables that influenced the incidence of nodal involvement. RESULTS: Lymphadenectomy was performed in 608 patients (83.8%); in these patients the rate of lymph node metastases was 13.6%. The median (range) number of nodes removed was 9 (1-43); there was a statistically significant correlation between the number of nodes removed and the percentage of nodal involvement (r = 0.6; P < 0.01). The rate of pN+ was significantly higher in the patients with >or= 13 than in those with < 13 nodes examined (20.8% vs 10.2%; P < 0.001). For organ-confined and locally advanced tumours there was a statistically significant difference in the pN+ rate between patients with < 13 or >or= 13 nodes examined (3.4% vs 10.5%, and 19.7% vs. 32.2%, respectively). CONCLUSIONS: The proportion of tumours classified as pN+ increased with the number of lymph nodes examined. In RCC,> 12 lymph nodes need to be assessed for optimal staging.

Adult↗
PubMed2002

Quantum information processing with large nuclear spins in GaAs semiconductors.

We propose an implementation for quantum information processing based on coherent manipulations of nuclear spins I=3/2 in GaAs semiconductors. We describe theoretically an NMR method which involves multiphoton transitions and which exploits the nonequidistance of nuclear spin levels due to quadrupolar splittings. Starting from known spin anisotropies we derive effective Hamiltonians in a generalized rotating frame, valid for arbitrary I, which allow us to describe the nonperturbative time evolution of spin states generated by magnetic rf fields. We identify an experimentally observable regime for multiphoton Rabi oscillations. In the nonlinear regime, we find Berry phase interference.

Journal Article↗
PubMed2001

Potential clinical value of circulating chromogranin A in patients with prostate carcinoma.

BACKGROUND: Neuroendocrine (NE) differentiation of prostate adenocarcinoma has received increasing attention in recent years as a result of possible implications for prognosis and therapy. The presence of NE tumor subpopulation can be gauged non invasively by measuring circulating levels of secretory products, primarily chromogranin A (CgA). METHODS: This article provides a review on published papers evaluating circulating CgA in prostate cancer patients. RESULTS: Circulating CgA levels were found to be higher in prostate cancer patients than in patients with benign or pre-malignant prostatic diseases. In patients with malignancy, they correlated either to the stage of disease or to the condition of hormone refractoriness. CgA levels did not correlate with serum prostate specific antigen (PSA) and were supranormal in the majority of advanced patients with PSA within normality. In hormone refractory cases, elevated CgA was a significant predictor of poor prognosis, independently from serum PSA. CgA values were not substantially affected by either endocrine therapy or chemotherapy. They were found to increase during androgen deprivation in some cases and this trend preceded that of PSA. The administration of a somatostatin analog in hormone refractory cases was able to reduce plasma CgA values consistently. CONCLUSIONS: Present data suggest a potential role of circulating CgA in the management of prostate cancer patients. CgA determination may be useful diagnostically and prognostically and could offer complementary information with respect to PSA. Serial evaluation of circulating CgA could provide information on changes in the NE phenotype expression as a consequence of tumor progression and/or treatment administration.

Androgen Antagonists↗
PubMed2000

[Pelvic ultrasound monitoring of lymphocele in patients treated with radical prostatectomy].

Pelvic lymphoceles, occurred in patients undergone radical retropubic prostatectomy, are believed to increase the risk of deep venous thrombosis and so thromboembolic complications. The authors' aim is to evaluate the usefulness of pelvic ultrasonography in the diagnosis and in the possible early treatment of pelvic lymphoceles. Fifty-eight patients undergone radical prostatectomy and pelvic lymphadenectomy, between January '98 and December '99, underwent a pelvic ultrasonography in VII post-operative day. When a symptomatic or large (over 5 cm) lymphocele was found, it was treated with ultrasound (US) guided drainage. In the study, the following parameters were considered: lymphocele occurrence, size, location and treatment and thromboembolic complication. Statistical analysis was carried out with Fisher's exact test. Pelvic US showed a lymphocele in 23 out of 58 (40%) patients. Mean size was 5 cm. Deep venous thrombosis occurred in 4 patients, all with pelvic lymphoceles. No thromboembolic complications were recorded. In our experience, pelvic ultrasound has shown to be an easy e reliable tool for diagnosis and percutaneous treatment of pelvic lymphoceles.

Follow-Up Studies↗
PubMed1996

Primary thrombocythemia and pregnancy: treatment and outcome in fifteen cases.

Pregnancy in patients with primary thrombocythemia (PT) is reported to be often complicated by recurrent abortion and fetal growth retardation. Fifteen pregnancies in nine patients with PT are reported. Nine pregnancies had a good outcome, with the birth of a healthy infant. There were two spontaneous abortions and three intrauterine deaths. One pregnancy was electively terminated after extensive thrombosis in the splanchnic district requiring surgical entero-resection. In five pregnancies the mother received no treatment; in ten pregnancies acetylsalicylic acid (ASA) was prescribed to the mother as soon as she was found pregnant, subcutaneous heparin was added from the middle trimester in seven cases. In patients treated with ASA and subcutaneous heparin pregnancies had a good outcome. Administration of ASA and heparin during pregnancy appears to improve the outcome in patients with PT and can prevent severe maternal complications, but requires close monitoring.

Adult↗
PubMed1996

A new global test for the evaluation of the protein C-protein S system.

We have developed a simple screening assay for evaluating the global activity of the protein C/protein S system. The new test consists of measuring the prothrombin time (PT) with bovine thromboplastin before and after activation of the PC present in the plasma sample by PROTAC, derived from Agkistrodon contortrix snake contortrix venom. Prolongation of the PT was directly related to the activity of the PC/PS system. One hundred and nineteen thrombophilic patients including 36 with PC deficiency, 22 with PS defect, 35 with APC resistance and 26 with other genetic defects predisposing to thrombosis were tested with the new assay together with 112 healthy subjects. The new test showed a high sensitivity for detection of inherited defects related to the PC/PS system (92%, 91% and 97% for PC defects, PS defects and APC resistance, respectively). Since it can be performed automatically the test could be used to screen for patients predisposed to thrombosis due to impairment of the PC/PS system and those patients who might eventually require more extensive evaluation of the PC/PS system by single component assays.

Adult↗
PubMed1995

Reduced blood levels of coagulation inhibitors in chronic hemodialysis compared with CAPD.

The aim of this study was to measure the coagulation inhibitors in two groups of uremic patients treated with hemodialysis (HD) and continuous ambulatory peritoneal dialysis (CAPD) to evaluate the differences in anticoagulant activity. In 20 patients on HD and 20 on CAPD, mean age 66 +/- 8 and 58 +/- 14 years, respectively, the following parameters were determined between dialysis exchanges: protein C (PC), protein S (PS), antithrombin III (AT III), electrophoresis, prothrombin activation fragment (F1+2), alpha 1 antitripsin (alpha 1 AT), prothrombin time (PT), and activated partial thromboplastin time (PTT). The mean values of PC, PS, and AT III were respectively, 95.7 +/- 16 on HD and 92 +/- 23 on CAPD; 82.2 +/- 13.6 on HD and 90.5 +/- 13.6 on CAPD; the mean value F1+2 was 1.2 +/- 0.5 on HD and 1.04 +/- 0.5 on CAPD (p < 0.05). A good correlation between PS and AT III% functional activity (p < 0.03, r = 0.5) in both groups was found. More-over, PS functional activity was inversely correlated with duration of dialysis (p < 0.05, r = -0.3). HD patients showed a reduction of coagulation inhibitors compared with CAPD patients. Such a phenomenon could justify the increased thrombotic risk in HD patients. Since 80% of those on HD and only 20% of those on CAPD received erythropoietin (EPO), the prothrombotic state in HD could be due to reduced PS activity secondary to EPO treatment.

Aged↗
PubMed1993

[Effectiveness of ketanserin in the treatment of light-to-moderate arterial hypertension].

The above study was undertaken in order to demonstrate the efficacy of ketanserin in mild to moderate essential arterial hypertension. Twenty-two patients, mean age 49.7 yrs., were studied during 36 months. After a 15-day washout period with clinical and instrumental assessment of basal conditions, treatment with 40 mg ketanserin every 12 hrs. was started. Pressure, blood chemistry and instrumental investigation were carried out systematically and showed the hypotensive action of ketanserin as well as a significant (about 12%) rise in HDL-cholesterol.

Adult↗
PubMed1991

Factor VII clotting assay: influence of different thromboplastins and factor VII-deficient plasmas. CISMEL Study Group.

Being a putative predictor of ischemic heart disease, the measurement of factor VII (FVII) coagulant activity will be presumably requested to clinical laboratories with increasing frequency. To assess the influence on FVII assays of different thromboplastins and FVII-deficient plasmas we compared performances of all possible combinations of 5 thromboplastins and 6 deficient plasmas. The reproducibility of the clotting times of the dose-response curves for human and rabbit thromboplastins were acceptable (CV lower than 7%), whereas bovine thromboplastin had a higher CV. Reproducibility was very similar for all deficient plasmas when they were used in combination with a given thromboplastin. Responsiveness of the dose-response curve did not depend on the deficient plasma but rather on the thromboplastin: one rabbit thromboplastin was the least responsive, the bovine thromboplastin the most responsive, the human and the remaining two rabbit thromboplastins had intermediate responsiveness. Assay sensitivity to cold-activated FVII varied according to the thromboplastin: the bovine thromboplastin was the most sensitive, the human thromboplastin the least sensitive, of the three rabbit thromboplastins two were relatively sensitive, one was almost insensitive. In conclusion, our results indicate that thromboplastin rather than deficient plasma is the crucial factor in the standardization of FVII assay.

Adult↗
PubMed1989

The effect of some instruments for prothrombin time testing on the International Sensitivity Index (ISI) of two rabbit tissue thromboplastin reagents.

Two commercial rabbit tissue thromboplastins were calibrated against the International Reference Preparation for rabbit thromboplastin (coded RBT/79) by one laboratory using the manual technique, a semi-automatic electro-mechanical coagulometer and three different automatic photo-optical instruments. The calibration of the two reagents was performed in three and two different exercises, respectively, and showed good reproducibility of the procedure. The purpose of calibration is providing a formula for the assessment of the International Normalized Ratio (INR) for patients receiving oral anticoagulants. The World Health Organization (WHO) model for thromboplastin calibration leads to the equation INR = RISI, in which R is the prothrombin time ratio and ISI the International Sensitivity Index of the calibrated thromboplastin/instrument system. This equation was adequate for one reagent, but not for the other when it was used in combination with the four instruments. At therapeutic intensities of anticoagulation, the deviation from the WHO-model observed for the second reagent was clinically insignificant. The WHO model was fully adequate when the second reagent was used with the manual technique. For both thromboplastins, there were statistically significant differences in ISI between the four instruments. The largest difference--amounting to approximately 10%--was observed between two photo-optical instruments. The order of instruments with increasing ISI was the same for the two reagents. It is recommended that thromboplastin manufacturers specify the instruments used for calibration of their reagent.

Animals↗
PubMed1989

Automated amidolytic method for evaluating the activated partial thromboplastin time compared with a conventional coagulation method.

We report studies of the validity and clinical application of a new amidolytic method for evaluating the activated partial thromboplastin time (APTT) compared with a conventional clotting method. The results with the two methods were well correlated for normal plasma and plasma from hemophilia patients. Congenital deficiencies of of the intrinsic coagulation pathway other than hypo- and dysfibrinogenemia detected by the amidolytic method agreed with those detected by the clotting APTT. The results with the two methods for plasma from patients under heparin treatment were statistically different, suggesting a lesser sensitivity of the amidolytic method to heparinization. The use of the amidolytic APTT reagent in combination with factor VIII and IX deficient plasma allowed the measurement of both factors. The results obtained with normal and hemophilic plasma were in agreement with those obtained with the one-stage clotting method in all except two occasions. Even though the amidolytic method demonstrated the presence of the lupus anticoagulant in the majority of tested samples of known lupus subjects, it was less sensitive to the abnormality than the clotting method.

Adult↗
PubMedDate not supplied

Specific assays of hemostasis proteins: factor VII.

Factor VII (FVII) activity should be measured in order to evaluate the risk for coronary artery disease. The measurement of FVII by means of a standardized clotting method seems to be influenced by the thromboplastins used, while the FVII-deficient plasmas do not affect the results.

Blood Coagulation Tests↗
PubMedDate not supplied

The effect of instruments for prothrombin time testing on the international normalized ratio.

Prothrombin time (PT) testing is used for monitoring oral anticoagulant therapy, its result being usually expressed as international normalized ratio (INR). This is done using the international sensitivity index (ISI) specific of thromboplastin employed to carry out the test. In this way a good PT standardization may be achieved although the instruments used to calibrate the thromboplastins might influence the ISI value.

Administration, Oral↗