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Biomedical subjects

E Beretta

Publications and source records attributed to E Beretta.

At least 19 recordsLinked to original sources
PubMed2006

Pathological features as predictors of recurrence after radical resection of gastric cancer.

BACKGROUND: The aim of this study was to investigate the pattern and timing of recurrence and to determine associated risk factors after radical resection of gastric cancer including D2 dissection. METHODS: A total of 274 patients who had undergone radical resection of gastric cancer with nodal involvement or T3-4 tumour were randomized to receive chemotherapy or no further treatment (control group). Locoregional recurrence and distant metastasis were analysed in a competing risks framework, by estimating the crude cumulative incidence in each group. Multiple regression models were used to investigate the influence of treatment and pathological features on the risk of recurrence. RESULTS: Overall, the 7 year rate of locoregional relapse was 15.8 per cent and that of distant recurrence was 34.5 per cent. There was a significant association between pathological node (pN) stage and distant relapse (P < 0.001), and between pathological tumour (pT) stage and locoregional recurrence (P = 0.024). Chemotherapy had no significant effect on either locoregional or distant recurrence. CONCLUSION: The rate of locoregional recurrence after radical surgery for gastric cancer was lower than that in studies based on more conservative surgery. The pT stage was related to the rate of locoregional recurrence whereas pN stage had an impact on distant recurrence.

Adult↗
PubMed2006

Capecitabine chemoradiation for rectal cancer after curative surgery.

This study reports the tolerability and feasibility of capecitabine, an oral fluoropyrimidine, chemoradiation as postoperative treatment. Stage II-III rectal cancer patients received 2 cycles of bolus 5-FU (425 mg/m2) and leucovorin (LV) (20 mg/m2) on days 1-5 q3w followed by oral capecitabine (800 mg/m2 bid) continuously during pelvic radiotherapy (total 50.4 Gy). Two additional cycles of 5-FU/LV were finally administered. Forty-one radically resected patients (median age: 61 years) were enrolled. All patients were evaluable for safety. Grade 3 adverse events included: proctitis (n = 3, 7%), diarrhea (n = 5, 12%), and leukopenia (n = 1, 2%). The overall rate of grade 3 diarrhea and leukopenia was 15% (95% confidence interval, 5-29%). Capecitabine chemoradiation in the adjuvant setting is well tolerated and is convenient to administer. These results support the use and further study of capecitabine chemoradiation in radically resected rectal cancer patients.

Adenocarcinoma↗
PubMed2004

Management of papillary microcarcinoma of the thyroid gland.

DESIGN: To investigate the frequency, treatment and clinical behaviour of differentiated microcarcinoma of the thyroid gland (PTMC). PATIENTS AND METHODS: Out of 376 patients submitted to surgical treatment for differentiated thyroid cancer from June 1980 to October 2003, 77 had been identified has having a PTMC (63 females, 14 males; mean age 43+/-13 years). Sixty-seven patients (87%) met the AMES risk definition for low (group I) and 10 (13%) for high-risk (group II) definition. The surgical procedures were lobo-isthmusectomy (n=14) or subtotal thyroidectomy (n=20) and total thyroidectomy (n=43) with node dissection in 15 cases. Follow-up ranging from 9 to 274 months (mean 124+/-84). RESULTS: Overall patient survival rates were 100 and 94% at 20 years in groups I and II, respectively (p=ns). There were no significant differences in surgical complications and in survival in patients submitted to total thyroidectomy when compared to partial thyroid resection. The presence of cervical node metastasis did not affect patient survival (p=0.8). The overall mean survival time was 266 months. CONCLUSIONS: Despite the overall excellent prognosis, PTMC was associated with a 1% disease-related mortality, a 2.5% local recurrence rate, 1% lymph-node recurrence rate, and 1% distant metastasis rate. We recommend total thyroidectomy accompanied by modified neck dissection if enlarged nodes are diagnosed.

Actuarial Analysis↗
PubMed2002

Adjuvant chemotherapy in gastric cancer: 5-year results of a randomised study by the Italian Trials in Medical Oncology (ITMO) Group.

BACKGROUND: The aim of this study was to determine the efficacy of the EAP regimen (etoposide, adriamycin and cisplatin) followed by the Machover schedule (fluorouracil and folinic acid) given as adjuvant treatment to patients with poor prognostic factors (N+ or T3/4). PATIENTS AND METHODS: Before randomisation, the subjects were stratified on the basis of node involvement (N+ or N-) and the time from surgery to randomisation (< or = 21 days or > 22 days). The surgical procedures for sub-total or total gastrectomy with D2 dissection were standardised among the participating centres. RESULTS: Between December 1992 and December 1997, 274 patients were enrolled: 137 in the treatment arm and 137 in the control arm. The majority of the patients (90%) were N+. After a median follow up of 66 months (range 2-83), the 5-year overall survival (OS) was 52% in the treatment arm and 48% in the control arm [hazard ratio (HR) 0.93; 95% confidence interval (CI) 0.65-1.34]; the 5-year disease-free survival (DFS) was 49% and 44%, respectively (HR: 0.83; 95% CI 0.59-1.17). Among the patients with N-/N+ (1-6), the 5-year OS was 61% in the treatment group and 60% in the control group; in those with N+ (1-6), it was 42% and 22%. The treatment was completed by 87% of patients. Drug-related grade 3/4 WHO toxicities included leukopenia (21%), nausea and vomiting (14%), mucositis (9%), neutropenia (3%) and thrombocytopenia (2%). There were two deaths due to sepsis. CONCLUSIONS: Although our results are not statistically significant, there was a limited relative risk reduction in the patients receiving adjuvant therapy (17% in DFS and 7% in OS). The data suggest that D2 surgery may have a favourable impact on OS.

Adult↗
PubMed2002

Efficacy of a chemotherapy combination for the treatment of metastatic neuroendocrine tumours.

OBJECTIVES: Neuroendocrine tumours (NETs) are heterogeneous neoplasms for which there is no standard treatment. We have previously proposed an effective polychemotherapy (5-fluorouracil, dacarbazine and epirubicin), which only produced objective responses of brief duration. The present study aimed to assess in a multidisciplinary manner the efficacy of the same regimen at intensified doses in patients with advanced NETs. PATIENTS AND METHODS: Eighty-two consecutive patients entered the study, of whom 21 had inoperable, locally advanced disease and 61 had metastatic disease. Seventy-two patients were evaluated for objective, biochemical and subjective responses. Response rate, time to progression (TTP) and overall survival (OS) were evaluated based on histotype. RESULTS: An objective response was observed in 20 patients (intention-to-treat and standard analysis 24.4% and 27.8%, respectively). Complete biochemical and subjective responses were obtained in 25.1% and 38.9% of the cases. The median duration of treatment was 4 months and the objective responses had a median duration of 38 months. After a 60-month follow-up the median TTP and OS were 21 and 38 months, respectively. CONCLUSIONS: Our polychemotherapy regimen is effective, with long duration, and is well tolerated both for gastroenteropancreatic and lung NETs, as well as for tumours with a more aggressive clinical behaviour. The new WHO endocrine tumour histotyping, examining also the tumour biology, may give additional information for selecting patients to chemotherapy.

Adult↗
PubMed2000

Retinoic acid negatively regulates neuropeptide Y expression in human neuroblastoma cells.

Retinoids are involved in the regulation of development and differentiation in many tissues, including the nervous system, where they have been associated with some neurotransmitter systems. In the present study, we evaluated the effects of all-trans retinoic acid (RA) on the biosynthesis and secretion of neuropeptide Y (NPY), a widely expressed neuroregulatory peptide. The SH-SY5Y human neuroblastoma cell line has been used as the in vitro model system. Treatment with 10 microM RA induced a marked decrease in NPY gene expression after as little as 3-6 h of incubation and resulted in its almost complete suppression at 12-24 h and after a 6-day differentiating treatment. The NPY content in cell extracts and the NPY secreted and accumulated in the culture medium were also reduced by exposure to 10 microM RA at 12 and 24 h and at 6 days. Moreover, RA treatment for 6 days, but not for 24 h, resulted in a marked stimulation of proNPY processing to mature NPY. The presence of negative retinoic acid-response elements in the human NPY promoter (up to -1078 bp) was excluded by a computer search. When SH-SY5Y cells were treated simultaneously with 20 nM TPA and 10 microM RA for 24 h, the marked stimulatory effect of TPA alone was completely suppressed. These observations suggest that the expression of NPY in SH-SY5Y human neuroblastoma cells is negatively regulated by RA at the level of gene expression, probably by mechanisms involving the interaction of activated RARs with transcription factors (such as AP-1).

Blotting, Northern↗
PubMed2000

Calcium-sensing receptor expression and signalling in human parathyroid adenomas and primary hyperplasia.

OBJECTIVE: Both in vivo and in vitro evidence indicates that primary hyperparathyroidism is characterized by a reduced sensitivity to extracellular calcium ([Ca2+]o). The existence of alterations in the expression and signalling of calcium sensing receptor (CaSR) in parathyroid neoplasia is still uncertain. In order to clarify the role of CaSR in the reduced [Ca2+]o sensing of parathyroid neoplasia we investigated PTH secretion and intracellular effectors triggered by CaSR activation as well as the levels of expression of CaSR and CaSR coupled G proteins (Gq/G11) in parathyroid adenomas and primary hyperplasia. MATERIALS AND METHODS: The study included 27 parathyroid adenomas, 4 cases of primary hyperplasia and pools of normal parathyroid biopsies. Tissues were either snap frozen in liquid nitrogen or placed in sterile medium for cell dispersion. The effects of increasing [Ca2+]o on in vitro PTH release, intracellular cAMP levels and intracellular calcium ([Ca2+]i) in cells loaded with the Ca2 + indicator fura-2 were evaluated. CaSR mRNA levels were assessed by semiquantitative RT-PCR analysis, using GAPDH as internal standard, while CaSR protein was detected by western blot analysis using a specific polyclonal antibody. Purified antisera selective for G11alpha and Gqalpha were used to detect this class of proteins. RESULTS: In basal conditions (at 0.5 mM [Ca2+]o) in vitro PTH released ranged from 29.4 to 1186 pg/well/60 minutes. Increasing [Ca2+]o from 0.5 to 1, 2.5 and 5 mM caused a variable effect. One group (n = 7) showed a significant but partial reduction of PTH release (of 17 to 60% of basal levels) that occurred at physiological [Ca2+]o concentrations (1 mM) while the remainder showed either inhibition detectable only at 2.5 mM (n = 15) or total (n = 9) resistance to [Ca2+]o. In the responsive cells, [Ca2+]o (1-5 mM) caused a pertussis toxin-insensitive [Ca2+]i rise (ranging from 10% to 260%), due to Ca2+ release from intracellular stores, and an inhibition of forskolin-stimulated cAMP levels. By RT-PCR almost all tumours tested showed a substantial reduction in CaSR mRNA levels when compared to the normal tissue (CaSR/GAPDH ratio: 3.1 +/- 0.5 vs. 15.5 +/- 3.1; P < 0.001), which was confirmed by immunoblotting analysis demonstrating low levels of CaSR protein in tumour tissues. Moreover, low amounts of G11alpha and Gqalpha, the G proteins involved in CaSR coupling, were observed in the majority of pathological tissues. CONCLUSIONS: The study shows that the activation of the calcium sensing receptors expressed in adenomatous parathyroid glands modulates intracellular effectors in a similar way to those operating in the normal parathyroid. Although a reduction of calcium sensing receptor expression is probably involved in the poor inhibition of PTH release induced by [Ca2+]o, this is not the only factor altering [Ca2+]o sensing in parathyroid adenomas, since tumours characterized by different in vitro sensitivity to [Ca2+]o showed similar CaSR levels. The low content of G proteins of the Gq subfamily might represent an additional alteration leading to a defective [Ca2+]o sensing.

Adenoma↗
PubMed1999

Expression of a leptin receptor in immortalized gonadotropin-releasing hormone-secreting neurons.

Leptin is secreted by adipocytes and regulates food intake and energy balance through the activation of specific receptors (OB-R). Recent evidence suggests that it is also involved in the control of reproductive processes, by possibly acting on central and peripheral targets. In particular, it has been shown that leptin may indirectly stimulate GnRH release from hypothalamic fragments by acting on interneurons impinging on GnRH-secreting neurons. The possibility that leptin might additionally modulate the activity of GnRH-secreting neurons in a direct way has been addressed in the present study, by using the immortalized GnRH-secreting cell line GT1-7. The presence of OB-R messenger RNA (mRNA) (long form) was detected by RT-PCR analysis of total RNA from GT1-7 cells. An OB-R protein is also expressed in these cells, as shown by immunocytochemistry and by Western blot analysis. The latter has revealed the presence of a single immunoreactive OB-R with an approximate size of 130 kDa. To study the functionality of these receptors, the effect of leptin treatment on GnRH secretion and gene expression in GT1-7 cells were evaluated. Under static conditions, GnRH release was stimulated by exposure to low concentrations of leptin (10(-12) M after 30 min; 10(-10) M after 60 min). The 10(-12) M dose was selected for studying the effect of leptin on GnRH secretion under dynamic conditions. To this purpose, GT1-7 cells were placed in a perifusion system; treatment with leptin (10(-12) M) for 60 min stimulated GnRH release with no changes of pulse frequency. On the contrary, exposure to leptin (10(-12)-10(-10) M) for 1, 3, 6, and 24 h did not affect GnRH gene expression in GT1-7 cells. The present results indicate that GT1-7 cells possess OB-Rs and that leptin may directly affect their function. Taken together with the available reports, these findings suggest that leptin might participate in the regulation of reproductive processes by acting at multiple levels, both centrally and peripherally.

Animals↗
PubMed1998

Modeling and analysis of a marine bacteriophage infection.

A mathematical model for the marine bacteriophage infection is proposed and its essential mathematical features are analyzed. Since bacteriophage infection induces bacterial lysis which releases into the marine environment, on the average, 'b' viruses per cell, the parameter b epsilon (1, t infinity) or 'virus replication factor' is chosen as the main parameter on which the dynamics of the infection depends. We proved that a threshold b* exists beyond which the endemic equilibrium bifurcates from the free disease one. Still, for increasing b values the endemic equilibrium bifurcates toward a periodic solution. We proved that a compact attractor set omega within the positive cone exists and within omega the free disease equilibrium is globally stable whenever b < or = b*, whereas it becomes a strong uniform repeller for b > b*. A concluding discussion with numerical simulation is then presented.

Bacteria↗
PubMed1997

The problem of the spreading of a liquid film along a solid surface: a new mathematical formulation.

A new mathematical model is proposed for the spreading of a liquid film on a solid surface. The model is based on the standard lubrication approximation for gently sloping films (with the no-slip condition for the fluid at the solid surface) in the major part of the film where it is not too thin. In the remaining and relatively small regions near the contact lines it is assumed that the so-called autonomy principle holds-i.e., given the material components, the external conditions, and the velocity of the contact lines along the surface, the behavior of the fluid is identical for all films. The resulting mathematical model is formulated as a free boundary problem for the classical fourth-order equation for the film thickness. A class of self-similar solutions to this free boundary problem is considered.

Journal Article↗
PubMed1997

Modified neck dissection in the treatment of differentiated thyroid carcinoma.

The prognosis of differentiated carcinoma of the thyroid has been reported to be extremely favourable. Previous studies have concluded that lymph node metastasis do not affect survival rates in patients with differentiated thyroid carcinoma. Therefore, nodal metastasis has not been evaluated as a prognostic factor in recent definitions of risk groups. To determine the significance of nodal disease, we reviewed 219 consecutive patients with differentiated thyroid cancer (191 papillary, 14 follicular and 14 Hurtle cell carcinomas). Fifty-five patients were treated with modified neck dissection and all of them received adjuvant radioiodine. There were recurrences in 25 patients (11.4%), with follow-up ranging from 6 months to 14 years. Systemic disease occurred synchronously in two patients, and four patients died of thyroid carcinoma.

Adenocarcinoma↗
PubMed1996

A mathematical model for drug administration by using the phagocytosis of red blood cells.

A mathematical model for the delivery of drug directly to the macrophages by using the phagocytosis of senescent red blood cells is proposed. The model is based on the following assumption: At time t = 0 a preassigned red blood cell population n(0,a) = phi (a), a > 0, loaded by the drug, is injected in the blood circulation. Among the cells of that population only those with an age a > or = a (a = 120 days) will be phagocytosed by macrophages. Of course, the lifetime of the drug must be higher than a. Within the red blood cells it cannot be metabolized, neither can it diffuse through their membranes. The emphasis of the paper is on the mathematical properties and on the formulation of the control problem.

Drug Therapy↗
PubMed1995

Global stability of an SIR epidemic model with time delays.

An SIR disease transmission model is formulated under the assumption that the force of infection at the present time depends on the number of infectives at the past. It is shown that a disease free equilibrium point is globally stable if no endemic equilibrium point exists. Further the endemic point (if it exists) is globally stable with respect to the whole state space except the neighborhood of the disease free state.

Animals↗
PubMed1995

Total thyroidectomy in the treatment of thyroid cancer.

Considerable controversy exists about the most appropriate treatment for thyroid cancer. In this report the authors present their experience of 189 patients, all of whom had a total thyroidectomy between June 1980 and December 1993. The age of the patients ranged from 11 to 78 years (mean age: 42 years), there were 144 women and 45 men. Histological types were: 146 papillary, 16 medullary, 10 follicular, eight Hurtle, six insular and three undifferentiated. Coexistent lesions included: 22 thyroiditis, 17 adenomas, one Graves' disease and 22 benign goitre. Fifty-six (29.6%) patients had multifocal papillary cancer (bilateral in 45 cases). Surgical complications included 20 cases of transient recurrent laryngeal nerve palsy, 16 cases of transient and one of permanent hypoparathyroidism, and one respiratory obstruction due to bilateral recurrent laryngeal nerve palsy that required temporary tracheostomy. Two patients were reoperated on due to bleeding. Ninety per cent of patients were discharged within 3 days of thyroidectomy. One hundred and fifty patients were evaluated for 131I treatment by a standardized dosimetry procedure 4 weeks after surgery. Dosimetry was also used to calculate therapeutic 131I doses. Seventy-six patients did not show a 131I uptake above background levels, 56 underwent therapeutic 131I, while in the 18 patients who showed an abnormal uptake of 131I it was decided not to give the therapeutic dose. The authors conclude that total thyroidectomy can be performed with a minimum of permanent disability in patients with malignant thyroid tumours. The theoretical and practical advantages of this kind of surgical strategy make it the treatment of choice for thyroid cancer.

Adolescent↗
PubMed1993

An optimal time control problem for the administration of 2',3'-dideoxycytidine by using red blood cells as bioreactors.

The problem of optimal dosage is studied for the administration of ddCyd using erythrocytes as carriers and bioreactors. The volume of erythrocytes and the initial amount of drug to be loaded have to be determined in such a way that the duration of the therapeutic effect is maximized without exceeding the toxic threshold. It is found that the optimal control is unique and it is at the upper vertex of the set of the admissible controls. A more general case is also briefly discussed.

Drug Carriers↗
PubMed1990

Stability in chemostat equations with delayed nutrient recycling.

The growth of a species feeding on a limiting nutrient supplied at a constant rate is modelled by chemostat-type equations with a general nutrient uptake function and delayed nutrient recycling. Conditions for boundedness of the solutions and the existence of non-negative equilibria are given for the integrodifferential equations with distributed time lags. When the time lags are neglected conditions for the global stability of the positive equilibrium and for the extinction of the species are provided. The positive equilibrium continues to be locally stable when the time lag in recycling is considered and this is proved for a wide class of memory functions. Computer simulations suggest that even in this case the region of stability is very large, but the solutions tend to the equilibrium through oscillations.

Eukaryota↗