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1.
Diabetes ; 37(6): 780-6, 1988 Jun.
Article in English | MEDLINE | ID: mdl-2838353

ABSTRACT

The aim of this study was to investigate the influence of insulin on platelet function, both in vitro and in vivo. For the in vitro investigation, we evaluated whether insulin affects platelet function at a physiological hormone concentration by incubating the platelet-rich plasma (PRP) of fasting subjects with human regular insulin at the final concentration of 40 microU/ml for 30 min; we observed a significant reduction of platelet sensitivity to all the aggregating agents employed, i.e., ADP, platelet-activating factor (PAF), epinephrine, collagen, and Na+ arachidonate. To investigate whether the insulin effect on platelets is dose dependent, we incubated the PRP of fasting subjects with different concentrations of human regular insulin (40, 80, 120, and 160 microU/ml) for 5 min, and we observed that the insulin-induced reduction of platelet sensitivity to aggregating agents is a dose-dependent phenomenon. Furthermore, the comparison between the platelet responses after 5 and 30 min of incubation with insulin showed that the insulin effect on platelet aggregation is time dependent. The lack of specificity of its inhibiting activity suggests that insulin does not interfere with the initial binding of each aggregating agent at specific sites but does influence a common step of platelet aggregation. Our study rules out the possibility that insulin reduces platelet-function-modifying intraplatelet cAMP levels or thromboxane A2 production, because this hormone decreases the platelet concentrations of cAMP--a phenomenon that, per se, promotes platelet aggregation--and does not modify collagen or Na+ arachidonate--induced platelet production of thromboxane A2, measured by radioimmunoassay of its stable-metabolite thromboxane B2.(ABSTRACT TRUNCATED AT 250 WORDS)


Subject(s)
Insulin/pharmacology , Platelet Aggregation Inhibitors , Adenosine Diphosphate/antagonists & inhibitors , Adult , Arachidonic Acids/antagonists & inhibitors , Blood Platelets/drug effects , Blood Platelets/metabolism , Collagen/antagonists & inhibitors , Cyclic AMP/blood , Epinephrine/antagonists & inhibitors , Humans , In Vitro Techniques , Insulin/physiology , Male , Platelet Activating Factor/antagonists & inhibitors , Thromboxane B2/blood
2.
Diabetes ; 43(8): 1015-9, 1994 Aug.
Article in English | MEDLINE | ID: mdl-7518780

ABSTRACT

To investigate whether insulin reduces platelet aggregability through a modulation of the guanosine-3',5'-cyclic monophosphate (cGMP) concentrations, we determined by a radioimmunoassay the cGMP values in the platelet-rich plasma (PRP) obtained from 17 healthy volunteers and incubated for 3 min with different concentrations of human recombinant insulin (0, 240, 480, 720, 960, and 1,920 pM). Insulin induced a dose-dependent cGMP increase, from 18.5 +/- 3.3 to 42.0 +/- 6.4 pmol/10(9) platelets (P = 0.0001). This increase was completely blunted when PRP was preincubated for 20 min with the tyrosine kinase inhibitor genistein (10 microM) or with the guanylate cyclase inhibitor methylene blue (10 microM), but the increase remained highly significant (P = 0.003 and 0.009) when PRP was preincubated for 20 min with the phosphodiesterase inhibitor 3-isobutyl-1-methyl-xanthine (IBMX, 500 microM) or with the nitric oxide synthase inhibitor NG-mono-methyl-L-arginine (L-NMMA, 30 microM). Finally, the insulin-induced decrease of platelet aggregability to collagen and ADP was completely blunted when PRP was preincubated with 10 microM of the guanylate cyclase inhibitor methylene blue. This study demonstrates that the platelet anti-aggregatory effect exerted by insulin is attributable to the insulin-induced increase of cGMP that is due to a direct receptor-mediated platelet guanylate cyclase activation.


Subject(s)
Blood Platelets/metabolism , Cyclic GMP/blood , Insulin/pharmacology , Platelet Aggregation Inhibitors/pharmacology , Platelet Aggregation/drug effects , 1-Methyl-3-isobutylxanthine/pharmacology , Adenosine Diphosphate/pharmacology , Adult , Amino Acid Oxidoreductases/antagonists & inhibitors , Arginine/analogs & derivatives , Arginine/pharmacology , Blood Platelets/drug effects , Collagen/pharmacology , Female , Genistein , Guanylate Cyclase/antagonists & inhibitors , Humans , Insulin/administration & dosage , Isoflavones/pharmacology , Male , Methylene Blue/pharmacology , Nitric Oxide Synthase , Protein-Tyrosine Kinases/antagonists & inhibitors , Radioimmunoassay , Recombinant Proteins/administration & dosage , Recombinant Proteins/pharmacology , omega-N-Methylarginine
3.
Diabetes ; 45(6): 768-70, 1996 Jun.
Article in English | MEDLINE | ID: mdl-8635651

ABSTRACT

To investigate whether the insulin-induced increase of guanosine-3',5'-cyclic monophosphate (cGMP) in human platelets is mediated by nitric oxide or is influenced by the nitric oxide precursor L-arginine, we measured cGMP in platelet-rich plasma obtained from healthy volunteers incubated for 3 min with human recombinant insulin (0, 240, 480, 960, and 1,920 pmol/l) both with and without 1) a 20-min incubation with the nitric oxide-synthase inhibitor N(G)-monomethyl-L-arginine (L-NMMA) (50, 70, 100, and 1,000 micromol/l; n = 5 for each dose) and 2) a 20-min incubation with the nitric oxide precursor L-arginine (300 micromol/l; n = 6). In a first set of experiments, insulin induced a dose-dependent cGMP increase, from 9.8 +/- 0.8 to 45.6 +/- 5.5 pmol/10(9) platelets (P = 0.0001); in the presence of 1 mmol/l L-NMMA, this increase was blunted, cGMP being 8.9 +/- 1.4 and 11.1 +/- 2.2 pmol/10(9) platelets at 0 and 1,920 pmol/l insulin, respectively (NS). In the experiments with 70 and 100 micromol/l L-NMMA, the insulin effect on cGMP was inhibited, whereas 50 micromol/l L-NMMA did not blunt this insulin effect. In another set of experiments carried out to investigate the effects of L-arginine, insulin induced a dose-dependent cGMP increase, from 23.6 +/- 6.9 to 59.0 +/- 12.0 pmol/10(9) platelets (P = 0.0001); with L-arginine, basal cGMP values increased to 35.5 +/- 6.6 pmol/10(9) platelets (P = 0.05), and insulin maintained its ability to enhance dose-dependently cGMP values, which rose to 76.8 +/- 19.4 pmol/10(9) platelets (P = 0.003). This study carried out in human platelets demonstrates that the cGMP increase induced by insulin, which accounts for the antiaggregating effect of the hormone, is mediated by nitric oxide.


Subject(s)
Arginine/analogs & derivatives , Blood Platelets/metabolism , Cyclic GMP/blood , Enzyme Inhibitors/pharmacology , Insulin/pharmacology , Nitric Oxide/physiology , Adult , Analysis of Variance , Arginine/pharmacology , Blood Platelets/drug effects , Female , Humans , Male , Nitric Oxide Synthase/antagonists & inhibitors , Nitric Oxide Synthase/blood , Recombinant Proteins/pharmacology , omega-N-Methylarginine
4.
Diabetes ; 46(5): 742-9, 1997 May.
Article in English | MEDLINE | ID: mdl-9133539

ABSTRACT

The insulin-induced platelet anti-aggregating effect is attributed to a nitric oxide (NO)-mediated increase of cyclic guanosine monophosphate (cGMP). The aim of this work, carried out in human platelets, is to show whether insulin increases NO synthesis in platelets and whether it enhances not only cGMP but also cyclic adenosine monophosphate (cAMP) in these cells. We observed that 1) insulin dose-dependently increases NO production, evaluated as citrulline synthesis from L-arginine (n = 4, P = 0.015); 2) insulin dose-dependently increases not only cGMP but also cAMP: for instance, after 8 min of insulin incubation at 1,920 pmol/l, cAMP increased from 39.8 +/- 1.4 to 121.3 +/- 12.6 pmol/10(9) platelets (n = 16, P = 0.0001); 3) when insulin is incubated for 120 min, the increase of cGMP and cAMP shows a plateau between 2 and 20 min, and while the effect on cGMP is significant until 120 min, the effect on cAMP is no more significant at 60 and 120 min; 4) insulin increases the effects on cAMP of the adenylate cyclase agonists Iloprost and forskolin (n = 5, P = 0.0001) and enhances their platelet anti-aggregating effects (n = 6 and 8, respectively; P = 0.0001); and 5) the inhibition of NO synthase by N(G)-monomethyl-L-arginine blunts both the insulin effects on basal cGMP and cAMP (n = 4) and those on the Iloprost- and forskolin-induced cAMP increase (n = 5). Thus, insulin increases NO synthesis in human platelets, and, through NO, enhances both cGMP and cAMP. The platelet anti-aggregating effect exerted by insulin is, therefore, a NO-mediated phenomenon involving both cGMP and cAMP.


Subject(s)
Blood Platelets/drug effects , Cyclic AMP/blood , Cyclic GMP/blood , Insulin/pharmacology , Nitric Oxide/biosynthesis , Adult , Blood Platelets/chemistry , Blood Platelets/metabolism , Dose-Response Relationship, Drug , Female , Humans , Male
5.
Diabetes ; 35(7): 818-25, 1986 Jul.
Article in English | MEDLINE | ID: mdl-2941327

ABSTRACT

The aim of our study was to investigate the mechanisms involved in hypoglycemia-induced platelet activation. Sixteen healthy male subjects received a 60-min intravenous infusion of human regular insulin at the rate of 64 mU . m-2 . min-1: throughout 150 min, we serially measured plasma concentrations of glucose, insulin, and counterregulatory hormones; platelet sensitivity to ADP, thrombin and platelet-activating factor; plasma concentrations of platelet markers for specific proteins of in vivo release reaction (beta-thromboglobulin and platelet factor 4). Our study showed that insulin-induced hypoglycemia causes a significant increase in platelet sensitivity to aggregating agents in vitro and a platelet release reaction in vivo. Hypoglycemia-induced platelet activation was not correlated with plasma glucose concentrations at nadir and occurred before the increase of plasma growth hormone and cortisol. To further elucidate the mechanisms of hypoglycemia-induced platelet activation, we incubated in vitro platelet-rich plasma (PRP) of seven fasting healthy subjects with the same concentrations of insulin, epinephrine, glucagon, growth hormone, and cortisol measured in vivo during insulin-induced hypoglycemia. Only epinephrine was able to increase platelet sensitivity to aggregating agents. To investigate the role of alpha-adrenergic receptors in this phenomenon, we also studied four healthy subjects on another occasion, repeating the above-described insulin infusion together with intravenous infusion of phentolamine (-15 to +150 min), 5 mg over 2 min followed by 500 micrograms/min. alpha-Blockade was able to suppress hypoglycemia-induced increase of platelet sensitivity to aggregating agents.(ABSTRACT TRUNCATED AT 250 WORDS)


Subject(s)
Blood Platelets/physiology , Hormones/blood , Hypoglycemia/blood , Adult , Blood Platelets/metabolism , Epinephrine/blood , Glucagon/blood , Growth Hormone/blood , Humans , Hydrocortisone/blood , Insulin/blood , Male , Platelet Aggregation/drug effects , Platelet Factor 4/analysis , beta-Thromboglobulin/metabolism
6.
Diabetes ; 44(11): 1318-22, 1995 Nov.
Article in English | MEDLINE | ID: mdl-7589830

ABSTRACT

To investigate the effects of insulin on platelets in obesity and in non-insulin-dependent diabetes mellitus (NIDDM)--classic insulin-resistant states--we determined ADP-induced platelet aggregation and platelet cGMP (guanosine 3',5'-cyclic monophosphate) content in platelet-rich plasma obtained from nine obese subjects and nine age-matched healthy volunteers and from eight NIDDM obese patients and nine age-matched healthy volunteers after a 3-min incubation with human recombinant insulin (0, 240, 480, 960, and 1,920 pmol/l). Platelet aggregation was evaluated using different ADP doses to measure the ADP concentration determined on the basis of a dose-response curve necessary to elicit a maximal aggregation of 50% (ED50). Insulin induced a dose-dependent decrease of platelet aggregation to ADP (P = 0.0001) in healthy subjects. A significant effect was evident starting from an insulin concentration of 240 pmol/l. On the contrary, in insulin-resistant subjects, insulin reduced platelet sensitivity to ADP only at a concentration of 1,920 pmol/l. When ADP ED50 values obtained in platelet-rich plasma incubated with insulin were expressed in percentage of the ADP ED50 values obtained in platelet-rich plasma without insulin, considered as 100%, we observed that ADP ED50 with 1,920 pmol/l insulin was 153.6 +/- 13.2% in the younger healthy subject group (P = 0.004), 150.0 +/- 3.8% in the older healthy subject group (P = 0.0001), 116.1 +/- 6.1% in obese subjects (P = 0.031), and 120.0 +/- 8.6% in NIDDM patients (P = 0.05). In healthy subjects, insulin induced a dose-dependent increase of platelet cGMP (P = 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)


Subject(s)
Blood Platelets/physiology , Diabetes Mellitus, Type 2/blood , Diabetes Mellitus/blood , Insulin/pharmacology , Obesity/blood , Platelet Aggregation Inhibitors/pharmacology , Adenosine Diphosphate/pharmacology , Adult , Blood Platelets/drug effects , Blood Pressure , Case-Control Studies , Cholesterol/blood , Cholesterol, HDL/blood , Diabetes Mellitus, Type 2/physiopathology , Dose-Response Relationship, Drug , Female , Glycated Hemoglobin/analysis , Humans , In Vitro Techniques , Insulin/blood , Male , Recombinant Proteins/pharmacology , Reference Values , Triglycerides/blood
7.
Diabetes Care ; 11(2): 107-10, 1988 Feb.
Article in English | MEDLINE | ID: mdl-3289860

ABSTRACT

This study shows the influence on plasma glucose concentrations of 45 min of mild exercise (48 +/- 4% of maximum aerobic capacity) performed 180 min after breakfast and 195 min after a subcutaneous injection of regular insulin by six type I (insulin-dependent) diabetic patients on a three-daily insulin injection regimen (regular insulin before breakfast and lunch, regular + intermediate insulin before supper). It has been observed that such exercise does not induce a large plasma glucose decrease. Actually, plasma glucose concentrations were 99 +/- 18 mg/dl before exercise, reached a nadir of 78 +/- 17 mg/dl at 35 min, and were 81 +/- 15 mg/dl at the end of exercise. During the control study at rest, in the same 45-min time interval, plasma glucose decreased from 146 +/- 31 to 128 +/- 31 mg/dl. In the exercise study, one patient began exercising while hypoglycemic, and another patient developed asymptomatic hypoglycemia during exercise. In the control study at rest, one patient showed hypoglycemic glucose concentrations. Throughout the exercise study, plasma free-insulin concentrations decreased (from 32 +/- 5 to 20 +/- 4 microU/ml) as a result of the pharmacokinetics of subcutaneously injected insulin.


Subject(s)
Diabetes Mellitus, Type 1/blood , Insulin/administration & dosage , Physical Exertion , Adult , Blood Glucose/analysis , Diabetes Mellitus, Type 1/drug therapy , Drug Administration Schedule , Eating , Humans , Insulin/blood , Male , Time Factors
8.
Diabetes Care ; 21(1): 121-6, 1998 Jan.
Article in English | MEDLINE | ID: mdl-9538982

ABSTRACT

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.


Subject(s)
Blood Platelets/physiology , Diabetes Mellitus, Type 2/blood , Diabetes Mellitus/blood , Insulin/pharmacology , Nitroglycerin/pharmacology , Obesity/blood , Platelet Aggregation/drug effects , Thinness/blood , Adenosine Diphosphate/pharmacology , Adult , Analysis of Variance , Blood Glucose/analysis , Blood Platelets/drug effects , Blood Pressure , Body Mass Index , Cholesterol/blood , Cholesterol, HDL , Cyclic GMP/blood , Diabetes Mellitus/physiopathology , Diabetes Mellitus, Type 2/physiopathology , Female , Glycated Hemoglobin/analysis , Humans , Insulin/blood , Insulin Resistance , Male , Obesity/physiopathology , Platelet Aggregation/physiology , Platelet Aggregation Inhibitors/pharmacology , Reference Values , Triglycerides/blood
9.
Diabetes Care ; 15(11): 1742-6, 1992 Nov.
Article in English | MEDLINE | ID: mdl-1468311

ABSTRACT

OBJECTIVE: The aim of this study was to investigate whether a 45-min moderate exercise, performed postprandially with a timing that partially prevented the risk of hypoglycemia, was able to modify platelet function in patients affected by insulin-dependent (type I) diabetes mellitus without severe late complications and in a good metabolic control. RESEARCH DESIGN AND METHODS: We submitted 6 male type I diabetic patients (27.2 +/- 3.4 yr; body mass index, 21.4 +/- 0.6 kg/m2; HbA1c, 7.6 +/- 0.9%) on a daily three-insulin injection regimen, without severe late complications of diabetes, to a 45-min moderate exercise (about 50% of maximal oxygen consumption) with a cycle ergometer, beginning 180 min after breakfast and 195 min after a subcutaneous shot of regular insulin. Serial venous blood samples were conducted to measure plasma glucose, free insulin, counterregulatory hormones (glucagon, growth hormone, cortisol, and catecholamines), platelet sensitivity to ADP, platelet activating factor and collagen, and plasma concentrations of the platelet-specific protein beta-thromboglobulin (a marker of the platelet release reaction in vivo). RESULTS: Exercise was accompanied by a decrease of plasma glucose (from 5.9 +/- 1.2 to 4.6 +/- 1 mmol/L, P = 0.067) and free insulin (from 180 +/- 36 to 114 +/- 30 pmol/L, P = 0.003), and by a significant increase of growth hormone (from 5 +/- 1 to 15 +/- 4 micrograms/L, P = 0.045), cortisol (from 240 +/- 30 to 406 +/- 69 nmol/L, P = 0.018), epinephrine (from 1005 +/- 240 to 5143 +/- 1753 pmol/L, P = 0.077), and norepinephrine (from 5.04 +/- 1.08 to 13.48 +/- 2.98 nmol/L, P = 0.009). Platelet sensitivity to the agonists and plasma concentrations of beta-thromboglobulin increased during the exercise period. In particular, ADP ED50 reached during exercise 61 +/- 16% of basal values (P = 0.048), platelet activating factor ED50 reached 73 +/- 11% (P = 0.043), and collagen ED50 reached 68 +/- 9% (P = 0.008). beta-Thromboglobulin rose from 24 +/- 2 to 32 +/- 3 micrograms/L (P = 0.007). CONCLUSIONS: Moderate exercise enhances platelet function in type I diabetic patients without severe angiopathy and in a good metabolic control.


Subject(s)
Blood Glucose/metabolism , Blood Platelets/physiology , Diabetes Mellitus, Type 1/blood , Diabetes Mellitus, Type 1/physiopathology , Diabetic Angiopathies/physiopathology , Exercise/physiology , Adenosine Diphosphate/pharmacology , Adult , Collagen/pharmacology , Diabetes Mellitus, Type 1/drug therapy , Diabetic Angiopathies/blood , Eating , Epinephrine/blood , Growth Hormone/blood , Humans , Hydrocortisone/blood , In Vitro Techniques , Insulin/blood , Insulin/therapeutic use , Male , Norepinephrine/blood , Platelet Activating Factor/pharmacology , Platelet Activation/drug effects , beta-Thromboglobulin/metabolism
10.
Semin Oncol ; 24(1 Suppl 2): S2-38-S2-40, 1997 Feb.
Article in English | MEDLINE | ID: mdl-9045335

ABSTRACT

The clinical activity and toxicity of the triple combination of paclitaxel (Taxol; Bristol-Myers Squibb Company, Princeton, NJ), cyclophosphamide, and cisplatin was assessed in both previously treated and untreated women with advanced ovarian carcinoma. Paclitaxel 175 mg/m2 was administered over 3 hours following standard premedication (prednisolone, dexchlorpheniramine, and cimetidine). Cisplatin 80 mg/m2 and cyclophosphamide 600 mg/m2 were given 6 to 12 hours after paclitaxel. Treatment was given at 3-week intervals for six cycles. Twenty-seven patients entered the study; 23 were evaluable for toxicity and 17 for response. Paclitaxel appeared to add additional efficacy to the standard cisplatin/cyclophosphamide regimen. Both the overall and complete remission rates were very high (88% and 70%, respectively), and histologically confirmed complete remissions exceeded 60%. Longer follow-up is needed to determine the duration of these responses. The primary toxicities included leukoneutropenia, peripheral neuropathy, asthenia, and alopecia. Only two of 23 patients withdrew because of toxicity, however, and only two treatment cycles were complicated by neutropenic fever requiring intravenous antibiotics. No life-threatening toxicities were encountered, although the peripheral neuropathy was poorly and slowly reversible and may have a significant impact on the patients' quality of life.


Subject(s)
Antineoplastic Combined Chemotherapy Protocols/therapeutic use , Ovarian Neoplasms/drug therapy , Paclitaxel/administration & dosage , Adult , Aged , Antineoplastic Combined Chemotherapy Protocols/adverse effects , Cisplatin/administration & dosage , Cyclophosphamide/administration & dosage , Feasibility Studies , Female , Humans , Middle Aged , Neoplasm Staging , Ovarian Neoplasms/pathology , Remission Induction
11.
Semin Oncol ; 23(6 Suppl 15): 5-8, 1996 Dec.
Article in English | MEDLINE | ID: mdl-8996589

ABSTRACT

In this phase I/II study, we assessed the impact of paclitaxel (Taxol; Bristol-Myers Squibb Company, Princeton, NJ) in the treatment of advanced ovarian carcinoma combined with the standard regimen cisplatin/cyclophosphamide given as follows: paclitaxel 175 mg/m2 (over 3 hours perfusion with standard premedication), cisplatin 80 mg/m2 (6 to 12 hours after paclitaxel), and cyclophosphamide 400 mg/m2. From February 1994 to January 1996, 27 patients (median age, 55 years; age range, 35 to 74 years) were entered into the study. Eight patients had distant metastases and 19 had early locoregional disease (stage III, 18 patients; stage IC, one patient). Twenty-two patients had undergone prior surgery (simple biopsy, six patients; optimally debulked, nine patients; suboptimally debulked, seven patients). Twenty-one patients had received no prior chemotherapy and six were previously treated with at least one platinum-based regimen. A maximum of six courses of paclitaxel/cisplatin/cyclophosphamide were given every 21 days. Twenty-three patients were evaluable for toxicity: neutropenia (World Health Organization grade 3/4), 91% of patients; thrombopenia (World Health Organization grade 3/4), 13% of patients; two episodes of neutropenia with fever; and neurotoxicity grade 3, 17% of patients. Alopecia grade 3 was reported in all patients. No hypersensitivity reactions and no cardiac toxicity was observed. Among 17 patients evaluable for response (patients with stage IV disease or stage III suboptimally debulked), 12 (70%) clinical complete responses (CRs) and three (18%) partial responses were observed. Among the 12 patients with CRs, 10 underwent second-look laparotomy and seven of them (70%) achieved a pathologic CR. In the group of 11 chemotherapy-naive patients evaluable for response, eight (72%) achieved a CR and three (28%) achieved a partial response. This combination seems to be safe, with very acceptable toxicity, and also seems to be highly active in the treatment of patients with advanced ovarian carcinoma.


Subject(s)
Antineoplastic Combined Chemotherapy Protocols/therapeutic use , Ovarian Neoplasms/drug therapy , Adult , Aged , Cisplatin/administration & dosage , Cyclophosphamide/administration & dosage , Drug Administration Schedule , Female , Humans , Middle Aged , Paclitaxel/administration & dosage
12.
Metabolism ; 38(6): 501-3, 1989 Jun.
Article in English | MEDLINE | ID: mdl-2542723

ABSTRACT

This study investigates whether insulin influences the renin-angiotensin-aldosterone system in humans. Six healthy male volunteers were placed on a 30-minute euglycemic insulin clamp at 160 microU/mL; euglycemia was maintained also in the following 60 minutes by means of appropriate dextrose infusion. Throughout the study, plasma renin activity, angiotensin II, aldosterone, and factors involved in the regulation of the renin-angiotensin-aldosterone system were measured: catecholamines, angiotensin-converting enzyme, sodium, and potassium. A significant increase of plasma renin activity and angiotensin II was observed, and a decrease of aldosterone was also detected. These changes can be ascribed to the effects of the rapid insulin-induced plasma potassium decrease on plasma renin activity and aldosterone secretion because they did not occur in a control clamp study with a potassium infusion.


Subject(s)
Aldosterone/blood , Angiotensin II/blood , Insulin/pharmacology , Renin/blood , Adult , Blood Glucose/metabolism , Epinephrine/blood , Humans , Insulin/administration & dosage , Insulin/blood , Kinetics , Male , Norepinephrine/blood , Peptidyl-Dipeptidase A/blood , Potassium/blood , Sodium/blood
13.
Metabolism ; 42(9): 1081-3, 1993 Sep.
Article in English | MEDLINE | ID: mdl-8412756

ABSTRACT

This study sought to investigate whether insulin influences immunoreactive endothelin release from cultured human vascular smooth muscle cells. For this purpose, we incubated cultured vascular smooth muscle cells (VSMC) obtained from human microvessels with 0, 80, and 320 microU/mL insulin with or without arginine vasopressin (10 nmol/L) and angiotensin II (10 nmol/L). After 6 hours, the culture supernatant was collected and immunoreactive endothelin was determined by radioimmunoassay. Insulin at a concentration of 320 microU/mL induced a significant increase of immunoreactive endothelin levels in medium (from 15.2 +/- 0.8 to 20.6 +/- 0.8 pg/200 microL, P < .01) and potentiated arginine vasopressin- and angiotensin II-induced immunoreactive endothelin release (P < .0001 and P < .04, respectively). Insulin at a concentration of 80 microU/mL did not induce a significant increase of spontaneous immunoreactive endothelin release, but significantly increased the effects of arginine vasopressin (P < .05). In conclusion, insulin influences immunoreactive endothelin release from human VSMC in culture.


Subject(s)
Endothelins/metabolism , Insulin/pharmacology , Muscle, Smooth, Vascular/metabolism , Angiotensin II/pharmacology , Arginine Vasopressin/pharmacology , Cells, Cultured , Humans , Muscle, Smooth, Vascular/cytology , Radioimmunoassay
14.
Metabolism ; 45(3): 285-92, 1996 Mar.
Article in English | MEDLINE | ID: mdl-8606633

ABSTRACT

Nonenzymatic glycation of proteins is involved in the pathogenesis of diabetes vascular complications. Extracellular matrix proteins are a prominent target for nonenzymatic glycation because of their slow turnover rates. The aim of this study was to investigate the influence of human fibronectin (F) nonenzymatic glycation on adhesion and proliferation of cultured human vascular smooth muscle cells (hVSMC). Incubation of human F with 500 mmol/L D-glucose at 37 degrees C induced a time-dependent increase in fluorescence detectable at 440 nm after excitation at 363 nm. Nonenzymatic glycation did not affect binding of F itself to the plates. Adhesion of hVSMC to F increased with the increase of incubation time of the cells on the protein from 30 minutes up to 120 minutes and remained stable thereafter. Adhesion to glycated fibronectin (GF) was reduced in comparison to control F at all the different adhesion times. Adhesion of hVSMC to GF was reduced when F was exposed to glucose for 4, 9, or 28 days (P=.0417 to .0025), but not when F was exposed for 1 day. Adhesion of hVSMC to GF was reduced compared with adhesion to nonglycated F at all coating concentrations from 0.2 to 10 micrograms/mL (P=.05 to .014). Thus, nonenzymatic glycation of F impairs adhesion of hVSMC in vitro. Proliferation of hVSMC on F increased with increasing concentrations of the protein as coating agent (ANOVA:P<.0001 for both nonglycated F and GF). Proliferation with F glycated for 4, 9, and 28 days was reduced at concentrations of 1, 3, and 10 micrograms/mL as compared with proliferation with nonglycated F (P=.0253 to .0001). Proliferation on F glycated for only 1 day was not significantly reduced. When the number of hVSMC plated on control F was reduced by 25% to take into account the reduced adhesion, the number of cells that proliferated on F was still reduced. In conclusion, nonenzymatic glycation of F impairs adhesive and proliferative properties of hVSMC.


Subject(s)
Fibronectins/metabolism , Muscle, Smooth, Vascular/cytology , Cell Adhesion , Cell Division , Cells, Cultured , Glycosylation , Humans
15.
Article in English | MEDLINE | ID: mdl-2525784

ABSTRACT

The beta-adrenoceptor antagonist propranolol is used in the therapy of hypertension and ischemic heart disease. The aim of our study was to evaluate the effects of this drug on platelet aggregation and on synthesis of thromboxane B2 (the stable metabolite of Thromboxane A2) from platelet rich plasma (PRP), whole blood samples and during spontaneous clotting. The results indicate that propranolol at concentrations near the therapeutic range, significantly inhibit collagen and thrombin-induced platelet aggregation and TxB2 synthesis from PRP. Furthermore the drug demonstrates inhibitory activity on B-TG release and TxB2 production from whole blood samples and on spontaneous clotting. The results suggest that some benefits of propranolol in the treatment of patients with coronary artery disease or cardiovascular conditions associated with platelet hyperaggregability may also be related to interference with platelet activation "in vivo" and with TxA2 generation.


Subject(s)
Blood Platelets/metabolism , Platelet Aggregation Inhibitors/pharmacology , Platelet Aggregation/drug effects , Propranolol/pharmacology , Thromboxane B2/biosynthesis , Adult , Blood Platelets/drug effects , Collagen/pharmacology , Humans , In Vitro Techniques , Male , Thrombin/pharmacology , Thromboxane B2/blood , beta-Thromboglobulin/metabolism
16.
Article in English | MEDLINE | ID: mdl-7508131

ABSTRACT

The present study investigated the effect of a combination between the stable prostacyclin (PGI2) analogue iloprost and compounds, glyceryl trinitrate (GTN) and L-arginine-, which enhance the intraplatelet cyclic guanosine monophosphate (cGMP) levels on platelet aggregation, release reaction and cyclic nucleotide content: in particular cyclic adenosine monophosphate (cAMP) and cGMP. Iloprost inhibited in a dose-dependent way the platelet aggregation in response to collagen, adenosine diphosphate (ADP) and adrenaline and it increased the intraplatelet cAMP concentrations. GTN directly decreased the platelet responses and increased the intraplatelet levels of both cGMP and cAMP. GTN (20 x 10(-6) mol/l) and L-arginine (0.2 x 10(-3) mol/l) potentiated the inhibitory effects of iloprost on platelet aggregation and release reaction. Our results suggest: 1. A synergistic effect of the simultaneous increase of both cAMP and cGMP on the biochemical steps involved in the inhibition of the platelet response; 2. An influence of cGMP on cAMP accumulation.


Subject(s)
Arginine/pharmacology , Cyclic GMP/physiology , Iloprost/pharmacology , Nitroglycerin/pharmacology , Platelet Aggregation Inhibitors/pharmacology , Platelet Aggregation/drug effects , Second Messenger Systems/drug effects , 1-Methyl-3-isobutylxanthine/pharmacology , Adenosine Diphosphate/pharmacology , Adult , Blood Platelets/drug effects , Blood Platelets/metabolism , Collagen/pharmacology , Cyclic AMP/blood , Cyclic AMP/physiology , Cyclic GMP/blood , Drug Synergism , Endothelium, Vascular/physiology , Epinephrine/pharmacology , Humans , Intracellular Fluid/drug effects , Male , Platelet Factor 4/metabolism
17.
Article in English | MEDLINE | ID: mdl-1808624

ABSTRACT

The present study evaluated the effects of the calcium-channel blocking agent diltiazem on platelet aggregation and on synthesis of thromboxane B2 (the stable metabolite of thromboxane A2) from platelet-rich plasma (PRP) and whole blood samples. Our results showed that diltiazem inhibits collagen- and thrombin-induced platelet aggregation and TXB2 production from PRP. Since no significant interference with conversion of arachidonate to thromboxane A2 was demonstrated, inhibition of phospholipase A2 activity may be the prevailing mechanism of the diltiazem effect. The drug demonstrated a dose-related inhibitory activity on TXB2 synthesis from whole blood samples during spontaneous clotting or following stimulation with collagen or thrombin. The present results give further evidences for an antiplatelet activity of diltiazem and support the hypothesis that inhibition of platelet function contributes to the therapeutic efficacy of this drug in the treatment of cardiovascular diseases.


Subject(s)
Blood Platelets/metabolism , Diltiazem/pharmacology , Thromboxane B2/biosynthesis , Adult , Blood Platelets/drug effects , Collagen/administration & dosage , Collagen/pharmacology , Diltiazem/administration & dosage , Dose-Response Relationship, Drug , Humans , Male , Phospholipases A/antagonists & inhibitors , Phospholipases A2 , Platelet Aggregation/drug effects , Platelet Aggregation Inhibitors/pharmacology , Thrombin/pharmacology , Thromboxane B2/blood
18.
Thromb Res ; 82(1): 57-68, 1996 Apr 01.
Article in English | MEDLINE | ID: mdl-8731510

ABSTRACT

In this study, we investigated the effects of a 3-min insulin incubation both at physiological and at supraphysiological concentrations on platelet aggregation and intraplatelet cyclic guanosine monophosphate (cGMP) levels both in the absence and in the presence of phosphodiesterase inhibition. We observed that insulin at concentration in the range 0.25-2 nmol/L decreases platelet response to adenosine 5-diphosphate (ADP), being Effective Dose 50 (ED50) for ADP with 2 nmol/L insulin 164 +/- 15% of the basal value, p = 0.005; furthermore, insulin increases intraplatelet content of cGMP (from basal 7.3 +/-0.6 pmol/10(9) plts to 14.6 +/- 1.2 pmol/10(9) plts with 2 nmol/L insulin, p=0.0001) and does not affect the platelet cGMP increase induced by nitrates. On the contrary, at very elevated concentrations (25-200 nmol/L) insulin increases platelet aggregation to ADP (ADP ED50 with 200 nmol/L insulin being 81 +/- 4% of the basal value, p = 0.01), decreases intraplatelet content of cGMP (from basal 7.2 +/- 0.1 pmol/10(9) plts to 5.7 +/- 0.2 pmol/10(9) plts with 200 nmol/L insulin, p = 0.01) and attenuates the platelet cGMP increase induced by nitrates. When cGMP catabolism is inhibited by theophylline or the selective cGMP phosphodiesterase inhibitor zaprinast, insulin shows anti-aggregating effects also at highly supraphysiological concentration (25-200 nmol/L). These results indicate that insulin, depending on the concentrations employed, shows opposite effects on platelet function, and they provide information about the mechanisms involved: actually, insulin is able to increase both cGMP synthesis, through guanylate cyclase activation, and cGMP catabolism, through phosphodiesterase activation. At physiological or slightly supraphysiological concentrations the first phenomenon is prevailing, so that cGMP intraplatelet values increase and insulin shows antiaggregating properties, whereas, at supraphysiological concentrations, insulin reduces cGMP levels through a prevailing phosphodiesterase activation, as supported by the fact that, when cGMP catabolism is prevented, insulin shows anti-aggregating properties also at the highest concentrations used.


Subject(s)
Insulin/administration & dosage , Platelet Aggregation/drug effects , Adenosine Diphosphate/pharmacology , Adult , Cyclic GMP/blood , Dose-Response Relationship, Drug , Female , Humans , Male , Nitroglycerin/pharmacology , Phosphodiesterase Inhibitors/pharmacology , Phosphoric Diester Hydrolases/blood , Platelet Aggregation Inhibitors/pharmacology , Purinones/pharmacology , Theophylline/pharmacology , Vasodilator Agents/pharmacology
19.
Thromb Res ; 77(5): 399-410, 1995 Mar 01.
Article in English | MEDLINE | ID: mdl-7778055

ABSTRACT

Picotamide is a new antiaggregating agent influencing the platelet prostaglandin pathway through an inhibition of thromboxane A2 (TXA2) synthesis and a competitive antagonism of platelet TXA2 receptors. In the present study, we investigated the in vitro effect of this drug on human platelet aggregation induced by different agents (adenosine 5'-diphosphate [ADP], collagen, Na arachidonate) both in platelet-rich plasma (PRP; Born's method) and whole blood (WB; impedance method). For each aggregating agent, ED50 value (agonist concentration necessary to induce a maximal aggregation of 50%) was determined in control samples and following addition of different picotamide concentrations on the basis of dose-response curves. Picotamide decreased the response to each aggregating agent in both WB and PRP samples. In WB, 25 microM picotamide was able to induce a highly significant enhancement of ED50 values for ADP (from 6.6 +/- 1 microM to 12.7 +/- 1.7 microM, p < 0.01), Na arachidonate (from 740 +/- 240 microM to 1,080 +/- 280 microM, p < 0.01) and collagen (from 2.4 +/- 0.3 micrograms/ml to 3.8 +/- 0.15 micrograms/ml, p < 0.01). In PRP, the same picotamide concentration significantly enhanced ED50 for each aggregating agent (from 2.0 +/- 0.1 microM to 3.1 +/- 0.3 microM for ADP, p < 0.01; from 960 +/- 80 microM to 1,850 +/- 260 microM for Na arachidonate, p < 0.001; from 3.0 +/- 0.3 microgram/ml to 5.0 +/- 0.8 micrograms/ml for collagen, p < 0.01). Present results show that picotamide effect on platelet response is present also in WB. Data might support the use of picotamide as antiaggregating agent in vascular diseases.


Subject(s)
Phthalic Acids/pharmacology , Platelet Aggregation Inhibitors/pharmacology , Platelet Aggregation/drug effects , Thromboxanes/antagonists & inhibitors , Adenosine Diphosphate/antagonists & inhibitors , Adult , Analysis of Variance , Arachidonic Acid/antagonists & inhibitors , Collagen/antagonists & inhibitors , Humans , In Vitro Techniques , Male , Platelet Aggregation/physiology , Thromboxane B2/antagonists & inhibitors
20.
Am J Clin Oncol ; 18(5): 421-4, 1995 Oct.
Article in English | MEDLINE | ID: mdl-7572760

ABSTRACT

Tamoxifen (TAM) has been reported to enhance cisplatin (CDDP) cytotoxicity in experimental and clinical melanoma studies. Based on our previous experience with sequential cisplatin-interleukin-2 (IL2)-interferon (IFN), we performed a phase II study of TAM combined with our original CDDP-IL2-IFN regimen in 22 pretreated metastatic melanoma patients. With a 41% response rate (95% CI, 21-61) we confirmed the interesting antitumor activity of CDDP-IL2-IFN combination; however, TAM enhanced neither the response rate nor the duration of response, but appeared to induce significantly more myelotoxicity, as compared to our previous results with CDDP-IL2-IFN alone. Whereas mechanisms by which TAM may modulate CDDP cytotoxicity in melanoma tumors remain unknown, the exact place of TAM, if any, and its safety in chemotherapeutic or chemoimmunotherapeutic combinations require further investigations.


Subject(s)
Antineoplastic Combined Chemotherapy Protocols/therapeutic use , Immunotherapy , Melanoma/drug therapy , Melanoma/secondary , Adult , Cisplatin/administration & dosage , Female , Humans , Interferon alpha-2 , Interferon-alpha/administration & dosage , Interleukin-2/administration & dosage , Male , Melanoma/therapy , Middle Aged , Recombinant Proteins , Tamoxifen/administration & dosage
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