Giacomo Tamponi

Thromboelastogram monitoring in the perioperative period of hepatectomy for adult living liver donation

Living donor liver transplantation (LDLT) is becoming a widespread procedure. However, the risk of surgical and medical complications in healthy donors is still a major concern. Hypercoagulability contributes to thromboembolic complications after surgery, but alterations of hemostasis after liver resection are difficult to predict. This study aims to define the perioperative coagulation profile of living liver donors by the use of both routine tests and thromboelastogram (TEG).

Studies on Mechanisms Involved in Hypoglycemia-Induced Platelet Activation

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 (β-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, epineph-rine, 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 α-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 μg/min. α-Blockade was able to suppress hypoglycemia-induced increase of platelet sensitivity to aggregating agents. A further study in vitro confirmed these results obtained in vivo, showing that incubation with phentolamine is able to inhibit the epinephrine-induced increase of platelet aggregation in response to ADP, thrombin, and platelet-activating factor. In conclusion, insulin-induced hypoglycemia deeply influences platelet function, causing an increase of platelet sensitivity to aggregating agents in vitro and a release reaction in vivo. Through α-adrenoreceptors, epinephrine is responsible for the hypoglycemia-induced increase of platelet aggregation in response to ADP, thrombin, and platelet-activating factor.

PCR-Detectable Nonneoplastic Bcl-2/IgH Rearrangements Are Common in Normal Subjects and Cancer Patients at Diagnosis but Rare in Subjects Treated With Chemotherapy

PURPOSE To assess whether nonneoplastic Bcl-2/IgH rearrangements act as a confounding factor in the setting of minimal residual disease analysis by evaluating their incidence in a panel of lymphoma-free subjects, including cancer-free donors and chemotherapy-naive and chemotherapy-treated cancer patients. PATIENTS AND METHODS A total of 501 nonlymphoma subjects have been assessed: 258 cancer-free patients and 243 patients with malignancies other than lymphoma, 112 of whom were chemotherapy-naive. Patients were primarily assessed by nested polymerase chain reaction (PCR), followed by real-time quantitative PCR if they scored positive. In addition, six initially PCR-positive cancer-free donors were prospectively reassessed by qualitative and quantitative PCR after 30 and 60 days. RESULTS The overall incidence of Bcl-2/IgH positivity was 9.6%, with a median number of 11 rearrangements per 1,000,000 diploid genomes (range, 0 to 2,845 rearrangements), as assessed by real-time PCR. The incidence was similar in healthy subjects and cancer patients at diagnosis (12% and 12.5%; P = not significant). In contrast, the incidence of this translocation was only 2.3% in chemotherapy-treated patients (P <.001). In addition, three initially PCR-positive cancer-free donors showed persistence of their rearrangements when assessed after 30 and 60 days. CONCLUSION The low incidence of nonneoplastic Bcl-2/IgH rearrangements following chemotherapy provides further evidence of the prognostic role of persistent PCR-positivity in the posttreatment molecular follow-up of follicular lymphoma patients.

Absence of (−)[3H]desmethoxyverapamil binding sites on human platelets and lack of evidence for voltage-dependent calcium channels

The two major pathways for Ca2+ entry into cells are potential-sensitive channels and receptor-operated channels. The main object of this investigation was to identify which mechanism regulates Ca2+ entry into human platelets. Platelet stimulation with thrombin, adenosine diphosphate, platelet activating factor and arachidonic acid resulted in a concentration-dependent 2.5-3-fold increase in cytoplasmic free calcium concentration over the basal levels (140 +/- 32 nM or 104 +/- 21 respectively) as measured with the fluorescent dyes Quin-2 and Fura-2. Adrenaline and collagen had no effect in promoting intracellular Ca2+ increase as measured with Quin-2 and little effect when measured with Fura-2. Incubation of Quin-2-loaded platelets with the calcium antagonists verapamil and diltiazem, which are known to inhibit Ca2+ entry from voltage-gated channels in many types of cells, over the concentration range 10(-8) - 10(-4) M did not alter significantly either the resting or the cytoplasmic free Ca2+ after stimulation of platelets by several agonists. Moreover, the calcium antagonists exhibited little or no effect on aggregation and 5-hydroxytryptamine secretion induced by platelet activating factor, adenosine diphosphate, collagen or arachidonic acid in whole blood, platelet-rich plasma or washed platelets when employed at concentration ranges as above. Similar results were obtained in washed thrombin-stimulated platelets. High doses of verapamil (but not diltiazem) inhibited platelet aggregation and secretion in response to adrenaline. Direct radioligand binding studies with (-)[3H]desmethoxyverapamil showed that platelet membranes have no receptors for this drug, suggesting that Ca2+ entry occurs in human platelets via a pathway different from potential-sensitive Ca2+ channels.(ABSTRACT TRUNCATED AT 250 WORDS)

Biochemical and immunologic abnormalities in peripheral blood T lymphocytes of patients with hemophilia A

Subset distribution, ecto‐5′nucleotidase (5′NT) activity, and the generation of allospecific cytotoxic T lymphocytes (CTL) were investigated in peripheral blood T lymphocytes from 39 hemophilia A patients divided into three groups: group A and group B (HIV‐patients with CD4:CD8 ratio < 1 and > 1 respectively), and group C (HIV+ patients). 5′NT activity was significantly decreased compared with healthy controls in groups B and C. In group B, this deficiency was attributable to expansion of CD8+ CD11+ suppressor cells. In group C, activated (HLA‐DR +) CD8+ cells were also present and contributed to 5′NT deficiency. The suppressor cell expansion seemed to be mainly related to AHF infusions, whereas HLA‐DR expression was related to HIV infection. CD11+ and HLA‐DR + cells were also expanded in the CD4+ subpopulation of all three groups, whereas CD4+ CD28+ lymphocytes were significantly decreased in group C only. Lastly, alloreactive cytotoxicity was decreased in group B and was normal in groups A and C.

Arterial and venous thrombosis in two Italian families with the factor V Arg506→Gln mutation

Abstract: APC resistance, due to a point mutation in factor V at amino acid position Arg506, has been identified as a major cause of inherited thrombophilia. Here we report the presence of the factor V Arg506→Gln mutation in 2 Italian families. In 1 family 3 subjects heterozygous and 2 subjects homozygous for the factor V Arg506→ Gln mutation were identified. The only subject who developed a thrombotic event was a 20‐yr‐old girl who was found to be homozygous for the factor V Arg506→Gln mutation. In the second family 10 subjects were identified to be heterozygous for the factor V Arg506 →Gln mutation; among them 2 developed a thrombotic event. In the same family 2 individuals were found to be homozygous for the mutation: the first had a myocardial infarction at age 25 yr and the second suffered from multiple episodes of deep venous thrombosis and had a stroke at age 24 yr. These data show that the risk of developing deep venous thrombosis for the carriers of the factor V Arg506→Gln mutation is high in the families investigated. Furthermore our data imply that the factor V Arg506 →Gln mutation in its homozygous form may relate to myocardial infarction and stroke.

Human Leukocyte Interferon-α Treatment for Chronic HCV-Related Hepatitis in Hemophilic Patients Previously Intolerant to Other Interferons-α

Thirty patients affected by hemophilia A or B or von-Willebrands disease and chronic posttransfusional active HCV hepatitis who developed major side effects during the course of a previous treatment with recombinant interferon-α (IFN-α) were studied. In all patients IFN-α therapy had to be discontinued and those who achieved a primary serologic and viral response to HCV relapsed within a few months. After a washout period, patients were retreated with human leukocyte IFN-α, 6 MU thrice weekly for 12 months. In about 90% of patients, a primary response, with normal AST and GGT values and undetectable HCV-RNA, was achieved within the third month of treatment and for the entire duration of treatment none of the patients had to discontinue therapy because of severe adverse reactions. During posttherapy follow-up only one patient relapsed. The human leukocyte IFN-α regimen looks to be very effective and safe for carriers of inherited clotting disorders who developed major side effects with recombinant IFN-α therapy for HCV-related chronic hepatitis.

Immunologic and virologic findings in hemophiliacs do not correlate with ecto-5′nucleotidase activity of peripheral blood lymphocytes. A difference with homosexual men

It has been recently demonstrated that ecto‐5′nucleotidase (5′NT) activity is significantly decreased in the peripheral blood lymphocytes (PBL) of homosexual men. This paper reports a study of PBL 5′NT activity in 38 hemophiliacs at risk for the acquired immunodeficiency syndrome (AIDS). The enzyme activity was correlated to the immunologic and virologic data. T‐cell subset distribution was unbalanced and directly correlated with the cumulative amount of AHF infused. PBL 5′NT activity, however, was similar to that of healthy controls. 6 patients displayed serum antibodies to the human immunodeficiency virus (HIV) but no decrease in PBL 5′NT activity. In conclusion, these data indicate that both heavily treated and seropositive as well as untreated hemophiliacs have normal PBL 5′NT activity. This striking dissimilarity between homosexual men and hemophiliacs suggests that some immunologic alterations leading to 5′NT deficiency occur in the former only.

PLATELET BEHAVIOR IN ESSENTIAL THROMBOCYTHEMIA: A STUDY OF 31 CASES

Essential thrombocythemia is a chronic myeloproliferative disorder and is an interesting biological model for the study of platelet functions (1); patients with ET display a large increase in circulating platelets (up to 3.2 x 106/mm3 in our series) together with multiple platelet disfunction (2, 3). We evaluated platelet behavior in a uniform series of 31 patients. A retrospective study was conducted in conjunction with a group of cardiologists in a search for a correlation between the results of these tests and the incidence of thrombosis. 16 men and 15 women, aged 24-72 yr, with ET were consecutively studied. 5 had been admitted to our emergency heart unit because of an acute thrombotic episode. The controls were 15 healthy sexand agematched volunteers. Secondary thrombocytosis was ruled out and the diagnosis was confirmed by bone marrow biopsy and cytogenetic evaluation. The number of circulating platelets at diagnosis was 0.7-

In vivo Platelet Activation in Lower Limbs Thrombophlebitis

Platelet activation in vivo was studied in patients with thrombophlebitis of the lower limbs. The parameters considered were the platelet aggregate ratio (PAR) and the beta-thromboglobulin (beta-tg) level, which were repeatedly evaluated from the disease onset up to 3 months later, during anticoagulating and antiaggregating therapy. A significant decrease of PAR was found, along with a significant rise of the beta-tg level at the onset of the disease, and these values slowly returned to normal on therapy course. The same parameters exceeded the normal range again when the patients arbitrarily suspended any drug assumption. The possible significance and implications of these findings are discussed.