Biomedical subjects

P Massucco

Publications and source records attributed to P Massucco.

At least 19 recordsLinked to original sources

PubMed2006

Randomized clinical trial of liver resection with and without hepatic pedicle clamping.

BACKGROUND: The purpose of this study was to compare the perioperative outcome of liver resection with and without intermittent hepatic pedicle clamping. METHODS: Between June 2002 and June 2004, 126 consecutive patients with resectable liver tumours were randomized to undergo resection with (63 patients) or without (63 patients) intermittent hepatic pedicle clamping. RESULTS: The transection time was significantly higher in the group without hepatic pedicle clamping. The blood loss per cm(2) was similar in the two groups: 2.7 ml/cm(2) in the group with versus 3.2 ml/cm(2) in group without hepatic pedicle clamping (P = 0.425). In the subset of patients with an abnormal liver, there were no differences in blood loss per transection surface: 3.1 ml/cm(2) in the group with versus 2.9 ml/cm(2) in the group without clamping (P = 0.829). The rate of blood transfusions was not higher in the non-clamping group. No differences were observed in the postoperative liver enzyme serum levels, the in-hospital mortality (one patient in each group) or the number of complications. CONCLUSION: This study showed clearly that liver resection without hepatic pedicle clamping is safe, even in patients with a diseased liver.

Aged↗

PubMed2006

Neoadjuvant chemotherapy and resection for initially irresectable colorectal liver metastases.

BACKGROUND: Hepatic surgery is the treatment of choice for resectable colorectal liver metastases. Neoadjuvant chemotherapy can downstage the tumour and enable surgery in up to 38 per cent of patients whose tumours were initially considered irresectable. METHODS: This prospective study included 150 patients who underwent hepatic resection over a 4-year period. One hundred and sixteen patients had resection without neoadjuvant chemotherapy (group 1) and 34 had chemotherapy before liver surgery (group 2). Perioperative features, survival and pattern of recurrence were compared. RESULTS: Median follow-up was 35.1 months. The in-hospital mortality rate was zero. Three-year overall survival in the two groups was comparable (P = 0.232). The 3-year disease-free survival rate was 21 per cent in the neoadjuvant group compared with 50.5 per cent in the immediate resection group (P < 0.001). Recurrence rates were 94 per cent (32 of 34) in group 1 and 66.4 per cent in group 2 (P = 0.001); extrahepatic recurrence, alone or associated with recurrence in the liver, was significantly more common in group 2 than in group 1 (78 versus 55 per cent; P = 0.016). Multivariate analysis revealed that resection of the recurrence was the most important independent prognostic factor for improved disease-free survival (relative risk 0.2; P < 0.001). Patients in group 2 had reduced disease-free survival (RR 1.8; P = 0.012). CONCLUSION: The recurrence rate among patients who had neoadjuvant chemotherapy and surgery for initially irresectable liver metastases was extremely high. Re-resection should be attempted whenever feasible.

Adult↗

PubMed2005

Phase II trial of primary radiation therapy and concurrent chemotherapy for patients with locally advanced pancreatic cancer.

OBJECTIVES: Primary chemoradiotherapy for locally advanced pancreatic cancer (LAPC) may improve local control, curative resection rate and long-term survival. We performed a phase II study to evaluate toxicity and activity of primary radiation therapy and concurrent chemotherapy with gemcitabine (GEM) twice weekly in patients (pts) with LAPC. METHODS: From 6/1999 to 6/2003, 23 LAPC pts received GEM 100 mg/m2 twice weekly in the first 15 pts and 50 mg/m2 in the last 8 pts, concurrently with radiotherapy (1.8 Gy/day for a total dose of 45 Gy). RESULTS: The treatment was completed in 19/23 pts. Toxicities: G3-4 hematological toxicity occurred in 35 and 4% respectively; G3 nausea and vomiting and gastrointestinal toxicity in 30%. Clinical benefit was found in 10/18 pts (55%). Overall response: partial response rate 4/18 (22%); stable disease 13/18 (72%); progressive disease 1/18 (6%). Six pts underwent pancreaticoduodenectomy with extended lymphadenectomy (5/6 pts pT3, 1/6 pts microscopic cancer foci, 1/6 N+, 5/6 negative retroperitoneal margin). MEDIAN SURVIVAL: 14 months for the entire group, 12 months for unresected pts, 20 months for resected pts. CONCLUSIONS: The treatment with GEM twice weekly at 50 mg/m2 associated with radiotherapy (45 Gy) is feasible and permits to obtain clinical benefit in a good percentage of pts. Objective response, median survival, and local and systemic control are similar to other studies and need further improvement.

Adolescent↗

PubMed2005

Liver resection for hepatocellular carcinoma on cirrhosis: analysis of mortality, morbidity and survival--a European single center experience.

AIMS: To evaluate short- and long-term results of liver resections and prognostic factors in cirrhotic patients with hepatocellular carcinoma. STUDY DESIGN: A single-unit, retrospective study analyzing 216 patients with histologically confirmed cirrhosis who underwent hepatic resection for hepatocellular carcinoma. All clinico-pathologic and follow-up data were collected prospectively. RESULTS: Child A patients had a significantly lower in-hospital mortality rate compared to Child B-C: 4.7 vs 21.3% (p=0.0003). Overall morbidity rate was 38.4%; multiple logistic regression analysis identified liver function, hepatic pedicle clamping time, number of nodes and transfusion rate as independent predictors for post-operative complications. Overall and disease-free 5-year survival rates were 34.1 and 25.2%. Multivariate analysis showed that Child A, radical resection, tumour size < or =5 cm and, absence of vascular invasion were independent prognostic factors for long-term survival. No significant differences in overall and disease-free survival were found according to the type of resection (anatomic vs non-anatomic). CONCLUSIONS: Patients with preserved liver function and small-size, single-node hepatocellular carcinomas are the best candidates for hepatic resection.

Aged↗

PubMed2004

Laparoscopy as a prognostic factor in curative resection for node positive colorectal cancer: results for a single-institution nonrandomized prospective trial.

BACKGROUND: Several studies reporting preliminary long-term survival data after laparoscopic resections for colonic adenocarcinoma did not show any detrimental effect in comparison with historic studies of laparotomies. A previous randomized study has reported an unforeseen better long-term survival for node-positive patients treated by laparoscopic colectomy. METHODS: A single-institution prospective nonrandomized trial compared short- and long-term results of laparoscopic and open curative resection for adenocarcinoma of the left colon or rectum in 255 consecutive patients from January 1996 to December 2000. RESULTS: In this study, 34 left hemicolectomy, 202 anterior resections, and 19 abdominoperineal resections were performed. A total of 74 patients underwent a laparoscopic resection (LR), and 181, an open resection (OR). The tumor site was the descending colon in 32 cases, the sigmoid colon in 98 cases, and the rectum in 125 cases, including 87 mid-low rectal cancers. Ten LR procedures (13.5%) were converted to open surgery. The hospital mortality was 0.08%, and in hospital morbidity was 16.2% for LR and 13.3% for OR (p = 0.56). The median postoperative stay was 1 day shorter for LR (9 days) than for OR (10 days) (p = 0.09). The mean number of lymph nodes retrieved were 13.8 +/- 5.7 for OR and 12.7 +/- 5; for LR (p = 0.23). Age exceeding 70 years, T stage, N stage, grading, mid-low rectal site, and laparoscopy were found by multivariate analysis to be significant prognostic factors for disease-free and cancer-related survival. When patients were stratified by stage, a trend toward a better disease-free and cancer-related survival was identified in stage III patients undergoing LR. CONCLUSIONS: Laparoscopic colonic resection is a safe procedure in terms of postoperative outcome and long-term survival. Multivariate analysis showed that laparoscopy is a positive prognostic factor for disease-free and cancer-related survival. The current data agrees with the data for the only randomized study reported so far. Both suggest a better outcome for node-positive patients treated by laparoscopy.

Adenocarcinoma↗

PubMed2004

Prescription of statins to dyslipidemic patients affected by liver diseases: a subtle balance between risks and benefits.

AIM: Statins reduce cardiovascular morbidity and mortality in the general population with an excellent risk-benefit profile. The most frequent adverse events are myopathy and increase in hepatic aminotransferases. In this review, we consider the role of liver in metabolism of statins, their potential hepatic toxicity and the guidelines for their prescription in patients affected by different liver diseases. DATA SYNTHESIS: Statin-induced hepatic toxicity: i) occurs in 1-3% of patients; ii) is characterized by increased aminotransferase levels; iii) is dose-related; iv) is frequently asymptomatic; v) usually reverts after dosage reduction or treatment withdrawal. Finally, after recovery, a rechallenge with the same or other statins may not result in increased aminotranferases. CONCLUSIONS: Caution is needed when prescribing statins to patients with liver disease, and liver toxicity should always be monitored during statin treatment. In particular, i) the potential hepatic toxicity requires frequent control of biochemical parameters related to hepatic cytolysis and cholestasis in all patients on statins; ii) administration of statins is counterindicated in patients with advanced or end-stage parenchymal liver disease due to the relevant impairment of their metabolism; iii) cholestatic disorders with secondary dyslipidemia do not require statin treatment even if relevant alterations of the lipid pattern are detected; iv) patients with acute liver disease of viral or alcoholic etiology should not receive statins until normalization of cytolysis enzymes; v) chronic hepatitis patients may be treated by statins if their cardiovascular risk is elevated and provided that careful follow-up is carried out to rapidly recognize the onset of further liver damage; vi) liver transplantation recipients affected by dyslipidemia induced by immunosuppressive therapy can be treated with statins under careful clinical control; vii) the benefits of statins should likely overcome the risks in the large majority of dyslipidemic patients affected by non-alcoholic hepatosteatosis, a disease frequently diagnosed in insulin-resistant subjects.

Alanine Transaminase↗

PubMed2004

Impaired synthesis and action of antiaggregating cyclic nucleotides in platelets from obese subjects: possible role in platelet hyperactivation in obesity.

BACKGROUND: Subjects with central obesity exhibit platelet hyperactivity, which is involved in the atherosclerotic process and therefore can account for the increased risk of cardiovascular morbidity and mortality. The aim of the study was to evaluate whether alterations of platelet function in obesity involve synthesis and/or action of the two antiaggregating cyclic nucleotides adenosine 3',5'-cyclic monophosphate (cAMP) and guanosine 3',5'-cyclic monophosphate (cGMP). MATERIALS AND METHODS: In platelets from 16 obese and 15 control subjects we investigated the influence on platelet responses to the Adenosine-5-diphosphate sodium salt (ADP) exerted by (i) prostacyclin analogue Iloprost (0.31-5 nmol L(-1)) and the cAMP analogue 8-bromo-cAMP (10-500 micro mol L(-1)); and by (ii) nitric oxide (NO) donor sodium nitroprusside (SNP) (5-100 micro mol L(-1)) and the cGMP analogue 8-bromo-cGMP (10-500 micro mol L(-1)). IC(50) (minimal concentration of each inhibitor necessary to reduce platelet response to ADP by half) was determined. Iloprost and SNP ability to increase cyclic nucleotides was also measured. RESULTS: Significantly greater IC(50) were observed in obese subjects than in healthy controls (1.59 +/- 0.16 vs. 0.80 +/- 0.08 nmol L(-1), P = 0.0001 for Iloprost, and 27.6 +/- 6.5 vs. 7.0 +/- 1.7 micro mol L(-1), P = 0.006, for SNP); when data from control and obese subjects were pooled together, IC(50) of Iloprost and SNP correlated with the homeostasis model assessment (HOMA IR), which is a parameter used to measure the insulin resistance (r = 0.588, P = 0.029 and r = 0.640, P = 0.006, respectively). Also the antiaggregating effect of 8-Br-cAMP and 8-Br-cGMP was smaller in the obese subjects. Finally, the ability of Iloprost to increase platelet cAMP and the ability of SNP to increase both cGMP and cAMP were reduced in obese subjects. CONCLUSIONS: Platelet resistance to the antiaggregating effects of prostacyclin and NO in obesity is attributable to impairment of cyclic nucleotide synthesis and action. As cyclic nucleotides are the main effectors of platelet antiaggregation, the resistance to them can account for platelet hyperactivity in obesity.

Adult↗

PubMed2003

Diabetic muscle infarction associated with multiple autoimmune disorders, IgA deficiency and a catastrophically poor glycaemic control: a case report.

We report a case of diabetic muscle infarction in a 22-yr-old woman, with an 11-yr history of poorly controlled Type 1 diabetes complicated by laser-treated pre-proliferative retinopathy, macroalbuminuria and severe autonomic neuropathy, also affected by IgA deficiency, autoimmune hypothyroidism, coeliac disease and polygenic familiar hypercolesterolaemia. She was admitted to our Hospital for pain to the left thigh hindering her from walking. The pain had appeared without trauma about 2 months before admission, and worsened progressively in spite of anti-inflammatory drugs. Clinical picture (localised tender mass without skin signs of inflammation in an afebrile patient) and laboratory data (erythrocyte sedimentation rate 113 mm in 1 hr, fibrinogen 635 mg/dl) suggested the diagnosis of diabetic muscle infarction. Magnetic resonance imaging (MRI) confirmed this hypothesis showing a hyperintense area in T2-weighted sequences at adductor muscle group with enhancement after intravenous contrast. Symptoms subsided over the following 4 weeks after bed rest, analgesics, aspirin and a good glycaemic control. The 3-month follow-up MRI showed total recovery. At hospital admission, the patient presented a very poor glycaemic control (HbA1c 15.5%). After discharge, she started--in order to avoid the weight gain associated with intensive insulin therapy--a daily intense isometric training, undergoing frequent hypoglycaemic episodes. In a few months, in spite of repeated laser treatment, retinopathy progressed to the proliferative stage with bilateral vitreous haemorrhages and visual acuity decreased dramatically notwithstanding vitrectomy. This case confirms the association of diabetic muscle infarction with poorly controlled long-standing diabetes with microvascular complications, suggests the possible role of autoimmunity, and underlines the risk of repeated hypoglycaemic episodes and isometric exercise in the progression of pre-proliferative retinopathy.

Adult↗

PubMed2002

Blood glucose pre-prandial baseline decreases from morning to evening in type 2 diabetes: role of fasting blood glucose and influence on post-prandial excursions.

BACKGROUND: To know the relationships between pre- and postprandial blood glucose (BG), i.e. BG profile shape, is a requisite for an appropriate therapy for type 2 diabetic patients. In non diabetic subjects, pre-breakfast, pre-lunch and pre-dinner BG are similar, so that BG postprandial excursions are superimposed on a stable BG preprandial baseline. We aimed to clarify: (a) whether BG preprandial baseline is stable also in type 2 diabetes and (b) whether fasting BG (FBG) influences the slope of BG preprandial baseline and the relationships between pre- and postprandial BG. DESIGN: We evaluated self-measured BG profiles of 237 type 2 diabetic patients on diet alone (M/F, 152/85; age 58.6 +/- 0.7 years; years from diagnosis 4.8 +/- 0.6; BMI 28.0 +/- 0.3 kg m-2): 536 profiles containing preprandial BG (corresponding HbA1c 6.8 +/- 0.06%) and 208 profiles containing both pre- and postprandial BG (corresponding HbA1c 6.8 +/- 0.09%). The profiles, measured by nurses, of 866 type 2 diabetic patients on diet alone were also considered (corresponding HbA1c 6.7 +/- 0.04%). RESULTS: In self-measured profiles containing only preprandial BG: (i) FBG (6.77 +/- 0.07 mmol L(-1)) is higher than pre-lunch BG (6.09 +/- 0.07 mmol L(-1)), P = 0.0001) and pre-dinner BG (5.84 +/- 0.06 mmol L(-1)), P =0.0001); (ii) the delta value between FBG and pre-dinner BG is correlated with FBG (r = 0.57, P = 0.0001), the highest FBG, the steepest the fall of BG preprandial baseline throughout the day. This trend is confirmed in profiles measured by nurses. In profiles containing both pre- and postprandial BG: (i) there is a trend to preprandial BG fall (P = 0.0001) and to postprandial BG increase (P = 0.0001) from morning to evening; (ii) postprandial excursions are influenced and sometimes masked by the slope of BG preprandial baseline, thus, in profiles with FBG < or = 6.7 mmol L(-1), all postprandial values are higher than FBG (P = 0.0001), whereas in profiles with FBG > 7.8 mmol L(-1), postprandial values are not significantly higher than FBG. CONCLUSION: In type 2 diabetes, the shape of BG profiles changes in relation to FBG, because it deeply influences the slope of BG preprandial baseline on which postprandial excursions are superimposed. Thus, before planning treatment policies, not only the extent of fasting and postprandial hyperglycaemia, but also the shape of profiles should be considered, to safely correct hyperglycaemia without inducing hypoglycaemia.

Blood Glucose↗

PubMed2001

Studies on inhibition of human platelet function by sodium nitroprusside. Kinetic evaluation of the effect on aggregation and cyclic nucleotide content.

In this study, we explored the ability of sodium nitroprusside to inhibit the aggregation of human platelets in platelet-rich plasma (PRP) and whole blood and its effects on intracellular levels of guanosine 3',5'-cyclic monophosphate (cGMP) and adenosine 3',5'-cyclic monophosphate (cAMP). The experiments investigated dose-dependent effects of nitroprusside starting from concentrations in the range of circulating levels achievable in vivo during drug administration in humans. Furthermore, we investigated the time-course of both antiaggregating action and the influence on cyclic nucleotide synthesis. Results showed that sodium nitroprusside inhibited the aggregation induced by adenosine 5-diphosphate (ADP) and collagen starting from concentration as low as 2 micromol/l. The IC(50) value for ADP-induced aggregation in PRP was 18.7+/-2.4 micromol/l. The inhibition of platelet aggregation showed a time-dependent behaviour and was not reversible within 90 min. The accumulation of intraplatelet cGMP in the presence of sodium nitroprusside exhibited a comparable time-course characterized by an early increase, a steady state and a late further increase. The time-course of cAMP synthesis was very similar to that of cGMP. Our data evidenced a long-lasting inhibition of platelet responses by sodium nitroprusside and excluded a desensitization of platelet guanylyl cyclase after 3-h exposure to nitric oxide (NO). Furthermore, they indicated a role of cAMP accumulation in the antiaggregating effects of nitroso donor: the simultaneous increase of intracellular content of cAMP and cGMP can synergize in the reduction of the platelet responses.

Adenosine Diphosphate↗

PubMed2001

N-acetyl-L-cysteine exerts direct anti-aggregating effect on human platelets.

BACKGROUND: N-acetyl-L-cysteine, a thiol compound, has been shown to potentiate the inhibition of platelet aggregation exerted by organic nitrates and to increase the anti-aggregating effect of L-arginine, which promotes endogenous synthesis of nitric oxide (NO) acting as substrate of platelet constitutive nitric oxide synthase (NOS). It is not known whether this thiol can exert direct effects on platelet aggregability. MATERIALS AND METHODS: 14 healthy male volunteers provided platelet samples to investigate whether N-acetyl-L-cysteine directly influences platelet function and intraplatelet levels of 3',5' cyclic guanosine monophosphate (cGMP), which represents the second messenger involved in NO-induced antiaggregation. Some experiments were repeated in the presence of NOS inhibitor NG-monomethyl-L-arginine (L-NMMA), of nitric oxide-sensitive guanylyl cyclase inhibitor 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ), of the selective cGMP phosphodiesterase inhibitor zaprinast and of calcium ionophores (A23187, ionomycin). RESULTS: N-acetyl-L-cysteine at 3000-6000 micromol L-1 decreases the responses of human platelets both in platelet-rich plasma (aggregation induced by adenosine 5-diphosphate) and in whole blood (aggregation induced by collagen). The anti-aggregating effect was prevented by preincubation with L-NMMA and guanylyl cyclase inhibitor ODQ. In resting platelets, N-acetyl-L-cysteine increased the levels of cGMP starting from a concentration of 3000 micromol L-1. Permeabilized platelets exhibited an increased sensitivity to the anti-aggregating effect of N-acetyl-L-cysteine. Also, cGMP phosphodiesterase inhibition or the increase in calcium availability, enhanced N-acetyl-L-cysteine effects on platelets. CONCLUSION: N-acetyl-L-cysteine exerts direct anti-aggregating effects through an increased bioavailability of platelet nitric oxide.

3',5'-Cyclic-GMP Phosphodiesterases↗

PubMed2001

Outcome of surgical treatment for chronic calcifying pancreatitis.

OBJECTIVE: To evaluate the short and long-term results of surgical treatment of calcifying chronic pancreatitis in our center. PATIENTS AND METHODS: We studied 55 consecutive patients operated on for chronic calcifying pancreatitis during a period of 12 years. The mean follow-up period was 6.2 years. Main outcome measures were operative mortality and morbidity, degree of pain control, diabetes onset, survival, and causes of death. RESULTS: The etiology was alcoholic in 48 patients and idiopathic in seven patients. A resection was performed in 78% of cases and a by-pass procedure was performed in 22%. Operative mortality was 3.6%; morbidity was 21.8%. A ductal adenocarcinoma was found in 3.6% of cases. The alcohol withdrawal rate was 78%. Complete pain control was achieved in 71.4% of the patients. Among diabetes, cirrhosis, type of surgery, smoking and alcohol abuse history, only alcohol withdrawal was associated with pain control (p < 0.03). A late reintervention was needed in only one patient in the by-pass group. Five and 10-year survival rates for the entire population were 80% and 61%, respectively. Among alcohol, cirrhosis, diabetes, and type of surgery, only the former was associated with survival (p < 0.003). Five-year actuarial survival was 55.6% for patients who continued drinking compared with 86.3% for ex-alcoholics. CONCLUSIONS: Surgical resection should be performed when required by the anatomical conditions because it was associated with good long-term pain control and low postoperative and late morbidity. Alcohol withdrawal has a key role for effective control of pain and prolonged survival.

Adult↗

PubMed1999

L-arginine modulates aggregation and intracellular cyclic 3,5-guanosine monophosphate levels in human platelets: direct effect and interplay with antioxidative thiol agent.

Platelet nitric oxide is involved in the control of aggregability via cyclic 3',5'-guanosine monophosphate synthesis. Since L-arginine provides a guanidino nitrogen group for nitric oxide synthesis through nitric oxide synthase activity, we tried to clarify whether an increased availability of this amino acid can directly modulate the response of human platelets. In our conditions, L-arginine (at 100-6000 micromol/L) was able to influence the response of human platelets stimulated with adenosine 5-diphosphate and collagen both in PRP and in whole blood. The anti-aggregating effect was not present when D-arginine was used. Permeabilized platelets exhibited an increased sensitivity to L-arginine. Also, an increased availability of Ca2+ enhanced L-arginine effect. L-arginine (at 120-500 micromol/L) increased cyclic 3',5'-guanosine monophosphate levels in resting platelets; the amino acid also determined an increase of cyclic 3',5'-guanosine monophosphate in platelets at the end of adenosine 5-diphosphate-induced aggregation. Nitric oxide synthase inhibitor N(G)-monomethyl-L-arginine prevented L-arginine effects on aggregation and cyclic 3',5'-guanosine monophosphate synthesis. Phosphodiesterase III inhibitor milrinone and antioxidative thiol N-acetyl-L-cysteine enhanced the effect of L-arginine on cyclic 3',5'-guanosine monophosphate. In conclusion, L-arginine exerts inhibitory effects on human platelet response through a nitric oxide-dependent synthesis of cyclic 3',5'-guanosine monophosphate. A positive interplay on platelet response between L-arginine and milrinone or antioxidative thiol N-acetyl-L-cysteine was evidenced.

Acetylcysteine↗

PubMed1999

Human vascular smooth muscle cells express a constitutive nitric oxide synthase that insulin rapidly activates, thus increasing guanosine 3':5'-cyclic monophosphate and adenosine 3':5'-cyclic monophosphate concentrations.

AIMS/HYPOTHESIS: Insulin incubation of human vascular smooth muscle cells (hVSMC) for 120 min increases both guanosine 3':5'-cyclic monophosphate (cGMP) and adenosine 3':5'-cyclic monophosphate (cAMP) and these effects are blocked by inhibiting nitric oxide synthase (NOS). These data suggest that insulin activates a constitutive Ca2+-dependent NOS (cNOS), not described at yet in hVSMC. To test this hypothesis, we evaluated in hVSMC: i) the kinetics of the insulin-induced enhancement of the two cyclic nucleotides; ii) the ability of nitric oxide (NO) to increase both cyclic nucleotides; iii) NO involvement in the short-term influence of insulin on both cyclic nucleotides; iv) the ability of insulin to increase NO production in a few minutes; v) the presence of a cNOS activity; vi) the expression of mRNA for cNOS. METHODS: In hVSMC incubated with insulin, NO donors and the Ca2+ ionophore ionomycin, we measured cAMP and cGMP (RIA); in hVSMC incubated with insulin and ionomycin we measured NO, evaluated as L-(3H)-citrulline production from L-(3H)-arginine; by northern blot hybridization, we measured the expression of cNOS mRNA. RESULTS: i) By incubating hVSMC with 2 nmol/l insulin for 0-240 min, we observed an increase of both cGMP and cAMP (ANOVA: p = 0.0001). Cyclic GMP rose from 0.74 +/- 0.01 to 2.62 +/- 0.10 pmol/10(6) cells at 30 min (p = 0.0001); cAMP rose from 0.9 +/- 0.09 to 11.65 +/- 0.74 pmol/10(6) cells at 15 min (p=0.0001). ii) Sodium nitroprusside (100 mol/l) and glyceryltrinitrate (100 micromol/l) increased both cGMP and cAMP (p = 0.0001). iii) The effects of insulin on cyclic nucleotides were blocked by NOS inhibition. iv) An increase of NO was observed by incubating hVSMC for 5 min with 2 nmol/l insulin (p = 0.0001). v) Ionomycin (1 micromol/l) enhanced NO production (p = 0.0001) and increased both cyclic nucleotides (p = 0.0001). vi) hVSMC expressed mRNA of cNOS. CONCLUSION/INTERPRETATION: Human VSMC express cNOS, which is rapidly activated by insulin with a consequent increase of both cGMP and cAMP, suggesting that insulin-induced vasodilation in vivo is not entirely endothelium-mediated.

Calcium↗

PubMed1999

Modulation of human platelet function by L-canavanine: differential effects of low and high concentrations.

L-Canavanine is a naturally occurring L-amino acid that interferes with L-arginine-utilizing enzymes owing to its structural analogy with this L-amino acid. In macrophages and polymorphonuclear leukocytes, which express inducible nitric oxide synthase (iNOS), L-canavanine is able to prevent the L-arginine-derived synthesis of nitric oxide (NO). Its effects on constitutive NOS (cNOS) are far less clear. Because human platelets synthesize NO from L-arginine through a cNOS and because intracellular NO levels modulate platelet function, we have investigated the effects of L-canavanine on parameters potentially influenced by NO, such as platelet levels of 3',5'-cyclic guanosine monophosphate (cGMP) and responses to different aggregating agents. In our experimental conditions, L-canavanine was able to influence the response of human platelets to different aggregating agents such as catecholamines, 5-hydroxytryptamine, and ADP. Low L-canavanine concentrations (10-100 micromol/l) decreased platelet responses, whereas a high concentration (1 mmol/l) was unable to exert antiaggregating effects. In resting platelets, L-canavanine reduced the levels of cGMP, starting from a concentration of 1 mmol/l; furthermore, at the same concentrations, it was able to reduce cGMP levels at the end of the aggregation induced by collagen. In conclusion, L-canavanine exerts differential effects on human platelets in relation to the concentrations: at low levels, it exerts antiaggregating effects by actions independent of NOS inhibition, whereas, at high levels, it inhibits NO synthesis and does not exert antiaggregating effects.

Adenosine Diphosphate↗

PubMed1999

[Surgical treatment of internal duodenal diverticulum. Report of 2 clinical cases].

Internal duodenal diverticulum is a rare disease. Nowadays, less than 100 cases are reported in Western literature. Even if it is a pathology of malformative origin, the first clinical manifestations occur quite always during the III decade. Main symptom is a violent, suddenly arisen, abdominal colic, often associated with meals and with spontaneous remission. Frequency of accesses is variable in time; in most serious cases, colics are so close to cause a considerable reduction of nutrition. Among diagnostical means, very useful are Rx enema (that offers pathognomonical images) and endoscopy, by which the formation can be visualized directly and its connection with papilla can be delineated. In some rare cases, differential diagnosis has to be made with cystic dilatations of bile duct, and particularly with type III according to Alonso-Lej classification or choledochocele. When such a distinction is not possible, differential diagnosis will be made on the basis of histological examination of the type of mucosa present in the internal aspect of the diverticulum. Therapy of symptomatic forms is surgery. The technique of choice is transduodenal diverticulectomy. Cannulation of bile duct is a useful means to found the papilla during intervention, to protect duodenal suture in the postoperative period and to control it radiologically. Two cases of internal duodenal diverticulum operated on in the last 2 years are described and diagnostical and therapeutical items are discussed.

Adult↗

PubMed1998

Platelet resistance to nitrates in obesity and obese NIDDM, and normal platelet sensitivity to both insulin and nitrates in lean NIDDM.

OBJECTIVE: Previous studies in our laboratory showed that the platelet anti-aggregating effect exerted by insulin, mediated by a nitric oxide (NO)-induced increase of guanosine-3',5'-cyclic monophosphate (cGMP), is lost in the insulin-resistant of obesity and obese NIDDM. It is not clear 1) whether the alterations observed in obese NIDDM patients are attributable to the obesity-related insulin resistance or to diabetes per se and 2) whether insulin-resistant states present a normal or a blunted response to NO. This study has been conducted to investigate 1) the platelet sensitivity to insulin in lean NIDDM and 2) the platelet sensitivity to an NO donor, glyceryl trinitrate (GTN), in obesity and in both lean and obese NIDDM. RESEARCH DESIGN AND METHODS: We determined 1) ADP-induced platelet aggregation and platelet cGMP content in platelet-rich plasma (PRP) obtained from 11 lean NIDDM patients, after a 3-min incubation with insulin (0, 240, 480, 960, 1,920 pmol/l) and 2) ADP-induced platelet aggregation and platelet cGMP content in PRP obtained from 9 obese subjects, 11 lean and 8 obese NIDDM patients, and 18 control subjects, after a 3-min incubation with 0, 20, 40, and 100 mumol/l GTN. RESULTS: Insulin dose-dependently decreased platelet aggregation in lean NIDDM patients (P = 0.0001): with 1,920 pmol/l of insulin, ADP ED50 was 141.5 +/- 6.4% of basal values (P = 0.0001). Furthermore, insulin increased platelet cGMP (P = 0.0001) from 7.5 +/- 0.2 to 21.1 +/- 3.7 pmol/10(9) platelets. These results were similar to those previously described in healthy subjects. GTN reduced platelet aggregation in all the groups (P = 0.0001) at all the concentrations tested (P = 0.0001), but GTN IC50 values were much higher in insulin-resistant patients: 36.3 +/- 5.0 mumol/l in healthy control subjects, 26.0 +/- 6.0 mumol/l in lean NIDDM patients (NS vs. control subjects), 123.6 +/- 24.0 mumol/l in obese subjects (P = 0.0001 vs. control subjects), and 110.1 +/- 19.2 mumol/l in obese NIDDM patients (P = 0.0001 vs. control subjects). GTN dose-dependently increased platelet cGMP in all the groups (P = 0.0001 in control subjects, lean NIDDM patients, and obese subjects; P = 0.04 in obese NIDDM patients). Values reached by obese subjects and obese NIDDM patients, however, were lower than those reached by control subjects (with 100 mumol/l of GTN, P = 0.001 and P = 0.0001, respectively). In healthy control subjects and in obese subjects, the insulin:glucose ratio, used as an indirect measure of insulin sensitivity, was positively correlated to GTN IC50 (r = 0.530, P = 0.008), further suggesting that the sensitivity to NO is reduced in the presence of insulin resistance. CONCLUSIONS: The insulin anti-aggregating effect is preserved in lean NIDDM; platelet sensitivity to GTN in preserved in lean NIDDM but is reduced in the insulin-resistant states of obesity and obese NIDDM. Resistance to nitrates, therefore, could be considered another feature of the insulin-resistance syndrome.

Adenosine Diphosphate↗

PubMed1997

Influence of protamine on adhesion, chemotaxis and proliferation of human vascular smooth muscle cells.

It has been shown that, in streptozotocin diabetic rats, protamine-retarded insulin administered in vivo stimulates intimal hyperplasia in balloon-injured carotid artery. The aim of this study was to evaluate the influence of protamine on cultured human vascular smooth muscle cells (h VSMC), by observing its effects on adhesion, chemotaxis and proliferation. hVSMC were isolated during abdominal surgery, cultured and utilized at passages 6-10. We observed that protamine stimulates: 1) cell adhesion in the concentration range 0.04-20 micrograms/ml (analysis of variance, ANOVA, p < 0.0001); 2) cell chemotaxis in the absence of fetal calf serum (FCS) in the concentration range 1-200 micrograms/ml (ANOVA, p < 0.0001) and in the presence of 1% FCS in the concentration range 5-200 micrograms/ml (ANOVA, p < 0.0001), further enhancing the chemotaxis induced by 10% FCS in the concentration range 20-200 micrograms/ml (ANOVA, p < 0.0001); 3) cell proliferation and 3H-thymidine incorporation from 1 to 5 micrograms/ml (ANOVA, p < 0.0001); 4) cell c-fos oncoprotein nuclear expression. We also observed that protamine effects on chemotaxis, proliferation and c-fos expression are inhibited by heparin that human insulin stimulates cell proliferation and 3H-thymidine incorporation (ANOVA, p < 0.0001) at concentrations equal to or greater than 480 pmol/l and that these effects of insulin persist in the presence of protamine. In conclusion, protamine influences hVSMC behaviour by interfering with biological functions involved in atherogenesis. The concentrations used in this short-term in vitro study were higher than those probably occurring in vivo in patients chronically treated by protamine-retarded insulin preparations: further studies, therefore, are needed to evaluate the safety of protamine as a retardant of insulin action in vivo.

Cell Adhesion↗