IMMUNOREACT 6: weak immune surveillance characterizes early-onset rectal cancer

BACKGROUND

Colon cancer in young patients is often associated with hereditary syndromes; however, in early-onset rectal cancer, mutations of these genes are rarely observed. The aim of this study was to analyse the features of the local immune microenvironment and the mutational pattern in early-onset rectal cancer.

METHODS

Commonly mutated genes were analysed within a rectal cancer series from the University Hospital of Padova. Mutation frequency and immune gene expression in a cohort from The Cancer Genome Atlas ('TCGA') were compared and immune-cell infiltration levels in the healthy rectal mucosa adjacent to rectal cancers were evaluated in the IMMUNOlogical microenvironment in REctal AdenoCarcinoma Treatment 1 and 2 ('IMMUNOREACT') series.

RESULTS

In the authors' series, the mutation frequency of BRAF, KRAS, and NRAS, as well as microsatellite instability frequency, were not different between early- and late-onset rectal cancer. In The Cancer Genome Atlas series, among the genes with the most considerable difference in mutation frequency between young and older patients, seven genes are involved in the immune response and CD69, CD3, and CD8β expression was lower in early-onset rectal cancer. In the IMMUNOlogical microenvironment in REctal AdenoCarcinoma Treatment 1 and 2 series, young patients had a lower rate of CD4+ T cells, but higher T regulator infiltration in the rectal mucosa.

CONCLUSION

Early-onset rectal cancer is rarely associated with common hereditary syndromes. The tumour microenvironment is characterized by a high frequency of mutations impairing the local immune surveillance mechanisms and low expression of immune editing-related genes. A constitutively low number of CD4 T cells associated with a high number of T regulators indicates an imbalance in the immune surveillance mechanisms.

Extended Distal Pancreatectomy for Cancer of the Body and Tail of the Pancreas: Analysis of Early and Late Results

Cancer of the body-tail of the pancreas often involves adjacent structures. Thus, surgical treatment may be extended to other organs or vessels in order to achieve radical resection. The aim of this study is to evaluate the safety and efficacy of extended distal pancreatectomy for ductal adenocarcinoma of the body and tail of the pancreas. Between January 2000 and December 2016, 101 patients underwent distal pancreatectomy (DP) for pancreatic cancer: 65 patients underwent standard-DP and 36 extended-DP, including the resection of the partial stomach (n = 12), adrenal gland (n = 7), liver (n = 7), colon (n = 8), celiac axis (n = 6), portal vein (n = 5), jejunum (n = 4) and kidney (n = 4). The two groups were compared in terms of their TNM classification, pathological grade, nodal status, state of resection margins, age, sex and levels of preoperative serum carbohydrate antigen 19-9 (CA 19.9). The morbidity and mortality were not statistically different in the two groups. The two groups disease-free and overall survival rates were significantly influenced by the tumor's stage, nodal status, pathological features and resection margins. Survival was not influenced by the extent of the surgical resection. However, when patients were stratified according to the type of extended resection, survival was worse in the group of patients undergoing vascular resection. Multivariate analysis showed that the stage and resection margins are independent predictors of disease-free and overall survival. Extended distal pancreatectomy may be performed with acceptable morbidity and mortality rates. Survival is not significantly different after standard or extended resection. However, the rate of tumor recurrence is high, and long-term survival is a rare event, especially in those patients who undergo distal pancreatectomy associated with vascular resection.

Antibody to Hepatitis G Mrus after a Vapour-Heated Factor Vlll Goncentrate

To evaluate whether or not clotting factor concentrates exposed to virucidal procedures transmitted hepatitis C, sera obtained in 1984–1986 from 27 previously untreated hemophiliacs infused with a vapour-heated factor VIII concentrate were tested retrospectively for the antibody to the hepatitis C virus (anti- HCV). A 2-year-old hemophiliac, negative for anti-HCV before administration of concentrate, seroconverted at week 12 and remained anti-HCV positive thereafter. Both his parents were anti-HCV negative and he had no other household contact. The patient had also become HBsAg positive at week 8 and had at the same time a marked elevation of alanine aminotransferase. His double infection with the hepatitis B and C viruses indicates that hot vapour was not completely effective in inactivating these viruses.

Thrombosis-free survival and life expectancy in 187 consecutive patients with essential thrombocythemia

A total of 187 consecutive patients with essential thrombocythemia (ET) were diagnosed and followed by our Hematology Department in the period October 1980-November 1994. The overall follow-up was 773 patient-years. Thrombosis-free survival and overall survival were calculated for the whole cohort; the same parameters were then calculated after arbitrary division of the cohort into two groups, according to the median age at diagnosis (55 years). Fifty percent of the patients had at least one thrombotic episode within 9 years after diagnosis. The thrombosis-free survival curves calculated for patients younger or older than 55 years at diagnosis were comparable. About 85% of the patients were alive 10 years after diagnosis. The survival curves for patients younger and older than 55 years at diagnosis were not significantly different in the observation period, and the observed mortality (seven patients) among patients younger than 55 years at diagnosis was significantly higher than expected (1.68 cases). The relative risk of death was four times greater (SMR = 4.17, 95% C.I. 1.6-8.6, p<0.01) than for healthy, age-matched people living in the same area. Age at diagnosis, smoking, sex, hypercholesterolemia, peak number of platelets, hypertension, and diabetes were not significant prognostic cardiovascular risk factors in our cohort. In conclusion, our data show that ET has to be considered a serious disease that significantly decreases both quality of life (expected life without thrombosis) and life expectancy for younger patients.

Microalbuminuria in IDDM is associated with increased expression of monocyte procoagulant activity

Microalbuminuria, the early phase of diabetic nephropathy, is associated with an increased risk of atherothrombosis. Monocytes play an important part in the pathogenesis of atherosclerosis and in the activation of haemostasis. However, procoagulant activity is poorly understood in Type I (insulin-dependent) diabetes mellitus, particularly in the presence of microalbuminuria. This study aimed to evaluate spontaneous and endotoxin-induced monocyte procoagulant activity in insulin-dependent diabetic patients with normoalbuminuria or microalbuminuria. Seventeen patients with microalbuminuria, 28 with normoalbuminuria and 26 healthy control subjects matched for age, sex, body mass index and smoking habit were studied. Mononuclear cells from peripheral venous blood were incubated with or without bacterial lypopolysaccharide. Spontaneous procoagulant activity and procoagulant activity after 3 h and 6 h of incubation were calculated. Spontaneous procoagulant activity values were similar in the three groups. After 3 h and 6 h incubation with bacterial lypopolysaccharide, procoagulant activity values were slightly, but not statistically significantly, higher in the normoalbuminuric diabetic group than in control group, and significantly higher in microalbuminuric diabetic group than in control group (p < 0.01). The increased endotoxin-induced monocyte procoagulant activity helps to explain the link between microalbuminuria and the increased risk of atherothrombosis in patients with Type I diabetes.

Use of modified functional assays for activated protein C resistance in patients with basally prolonged aPTT

Inherited resistance to activated protein C (APCr) is currently recognized as the most prevalent cause underlying venous thrombophilia, with an estimated prevalence around 20% in thrombotic patients and around 1.8-7% in the general population. A correct laboratory diagnosis of APCr is therefore essential. Two different diagnostic approaches are at present at our disposal: the semi-quantitative plasma test based on the measurement of two aPTTs (in the presence and absence of activated protein C), and the detection of the factor V Arg506 Gln mutation by DNA analysis. In this study we firstly evaluated sensitivity, specificity and diagnostic efficiency of an aPTT-based plasma clotting test (Chromogenix, Sweden) versus DNA analysis; then, since the APC resistance test is invalidated by a basally prolonged aPTT (i.e. during warfarin and heparin therapy or in patients with clotting factor deficiencies or in the presence of a lupus anticoagulant), patient plasmas were conveniently diluted in factor V deficient plasma in order to correct clotting factor abnormalities. Nevertheless, patients with a LA and an aPTT ratio range 1.8-3.17 were still all misclassified. We obtained correct diagnoses in LA positive patients by preincubating plasmas with a mixture of phospholipids; therefore we decided to perform a double modified clotting test adding a mixture of platelet derived phospholipids to samples previously diluted in factor V deficient plasma. The performance characteristics of this novel method with a different aPTT reagent (Behring, Germany) were also evaluated. With this double modified test all patients were correctly classified as negative or positive for factor V mutation in agreement with DNA analysis, irrespectfully of the basal aPTT value and the aPTT reagent employed. We propose this modified version of the APCr clotting test as an easily reproducible, reliable, very sensitive and specific screening test which possibly reduces the need for DNA analysis.

Natural and acquired inhibitors of hemostasis in selected symptomatic outpatients with venous thromboembolic disease

BACKGROUND AND OBJECTIVE

Deficiencies of natural inhibitors and the presence of lupus anticoagulant are important risk factors leading to venous thromboembolic events. Before resistance to activated protein C (APC-R) was identified, the overall prevalence of inherited abnormalities of hemostasis in non-selected outpatients with venous thromboembolic disease was under 10%. This cast doubts on the of cost effectiveness and clinical significance of assaying hemostasis inhibitors in all such patients. The goal of this study is to evaluate the prevalence of inherited and acquired abnormalities of hemostasis in younger symptomatic outpatients with objectively diagnosed venous thromboembolic disease (VTD).

METHODS

From October 1994 to October 1996, we diagnosed, treated and followed 191 consecutive outpatients with an objective diagnosis of venous thromboembolic disease, and assayed natural and acquired hemostasis inhibitors in 81 of them aged less than 50; in addition, 129 relatives of patients with inherited deficiencies were evaluated.

RESULTS

Twenty-six of the patients under age 50 showed inherited deficiencies of natural inhibitors (3 antithrombin, 5 protein C, 3 protein 5 and 14 APC-R, 1 dysfibrinogenemia) and 8 patients had lupus anticoagulant (LA): abnormalities of hemostasis were found in 41.9% (95% confidence interval 31.1-53.5). In older selected patients, 60% (95% confidence interval 40.6-77.3) of the subjects showed abnormalities. Seventy-two of the relatives displayed natural inhibitor deficiencies; 88.5% of the families studied had at least one relative with the same defect as the propositus.

INTERPRETATION AND CONCLUSIONS

A simple selection based on age, clinical and family history shows the existence of a high prevalence and the important clinical significance of abnormalities of hemostasis in symptomatic outpatients with venous thromboembolic disease.

Activated protein C resistance in type I diabetes

OBJECTIVE

To compare activated protein C (aPC) sensitivity in 37 type I diabetic patients and 33 healthy control subjects.

RESEARCH DESIGN AND METHODS

In this study, 37 type I diabetic patients and 33 healthy control subjects without personal or familial history of venous thrombosis and coagulation disorders, infections, intercurrent conditions, serum lupus anticoagulant, clinical cardiovascular complications, or drugs were examined.

RESULTS

The aPC ratio (aPTT [activated partial thromboplastin time] with and without aPC) was significantly lower in the type I diabetic patients than in the control subjects (P = 0.005).

CONCLUSIONS

These results suggest that the final steps of the protein C/S inhibiting system could be abnormal in type I diabetes.

Lupus anticoagulant and thrombosis: role of von Willebrand factor multimeric forms

OBJECTIVE

Patients with lupus anticoagulant (LA) have an increased incidence of venous and arterial thrombosis whose pathogenesis is still unclear. High molecular weight von Willebrand Factor (vWF) multimers seem to play a causal role in shear stress-induced platelet aggregation and thrombus formation. We studied whether in patients with LA, alterations in the vWF multimers might coexist.

METHODS

The multimeric composition of plasma vWF was analysed by SDS-electrophoresis and immunoblotting in 43 subjects positive for LA. About 2/3 of the patients had had either ischemic stroke, recurrent abortions, deep vein thrombosis (DVT) or a combination of these; the remaining subjects had never had any thrombotic events.

RESULTS

An abnormal vWf multimeric pattern was found in 16 patients (37.2%); no correlation was found with the diagnosis, but the presence of abnormal vWF significantly correlated with the site of the thrombosis: indeed, it was never detected in subjects with DVT, but was found in 71.4% of patients with multiple abortions, in 50% of those with stroke and even in 25% of non-thrombotic patients.

CONCLUSION

The hypothesis is put forward that abnormal VWF may represent an additional risk factor to LA for arterial thrombosis.

[Comparison of 2 low molecular weight heparins in patients undergoing major abdominal surgery]

INTRODUCTION AND AIMS

Thromboembolic disease can, in a large number of cases, be prevented in patients undergoing major surgery by using low molecular weight heparin (LMWH). These molecules extracted from standard heparin using a variety of cleavage methods possess different physical and chemical characteristics. The aim of this study was to compare two LMWH in the prevention of thromboembolism and in terms of safety.

METHODS

Thirty patients of both sexes were admitted to the study and underwent major abdominal surgery. Fifteen patients were treated with dalteparin sodium, 2500 IU, and fifteen with nadroparin calcium, 3075 IU. Subcutaneous administration was commenced two hours prior to surgery and continued for at least five days after the operation until the complete mobilisation of the patient. Six blood samples were taken from each patient in order to assay: aPTT, heparin, X factor, Quick time, ATIII, platelets and hemoglobin. Intraoperative bleeding and drainage were recorded for each patient.

RESULTS

The group treated with nadroparin showed a significant reduction in hemoglobin, correlated with greater blood loss (p < 0.05) compared to the group treated with dalteparin.

CONCLUSIONS

Both nadroparin and dalteparin showed good anti-Xa activity and safety, but although they possess the same pharmacodynamic characteristics, they should not be regarded as equal or interchangeable.

Factor V Arg506-->Gln mutation in patients with antiphospholipid antibodies

Antiphospholipid antibodies (APA) have thought to be implicated in the pathogenesis of both arterial and venous thrombosis. Because of heterogeneity of APA, direct evidence of their involvement in a thrombotic event is not yet available. Development of thrombosis in the antiphospholipid antibody syndrome (APS) may occur because of the presence of additional risk factors. Here we have analysed 60 patients with APA for the presence of the Arg506-->Gln mutation in factor V. Among them 26 suffered from deep venous thrombosis, 13 from arterial thrombosis and 21 had no history of arterial or venous thrombosis. In the first group four patients were found to be heterozygous and one homozygous for the factor V Arg506-->Gln mutation. None of the patients with the factor V mutation was found in the second and third group. The incidence of factor V mutation was significantly elevated in the group of patients with venous thrombosis. These data suggest that in patients with antiphospholipid antibodies the factor V Arg506-->Gln mutation may play a major role in the occurrence of venous thrombosis.

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

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.

Procoagulant activity of mononuclear cells is increased in myeloproliferative and myelodysplastic diseases

Procoagulant activity (PCA) of peripheral mononuclear cells (PMC) was evaluated in patients with primary thrombocythemia (PT, group A), polycythemia vera (PV), idiopathic myelofibrosis (IM) and myelodysplastic syndromes (group B), and in 15 healthy subjects as control group. PCA of PMC was assayed under basal conditions and after agonist-induced stimulation: bacterial lipopolysaccharide, glycosylated granulocyte-macrophage colony-stimulating factor, recombinant alpha-interferon. PCA was similar in the control group and group A when no stimulation was used, while PCA was found significantly higher in group B patients in the same conditions. In group A patients and in the control group, but not in group B patients, a lower PCA expression was found when PMC were simultaneously coincubated with LPS and alpha-interferon with respect to LPS incubation alone.

Reversal of doxorubicin resistance by the amiloride analogue EIPA in multidrug resistant human colon carcinoma cells

Although multidrug resistance (mdr) may arise through a variety of mechanisms, the most widely studied and accepted form is associated with an increased concentration of P-glycoprotein (P-gp), a 170 kd protein found in the membrane fraction of a number of mammalian cells. Since mdr seems to be related to the ability of resistant cells to extrude drugs and the circumvention of mdr is supposed to be due to the restored ability to accumulate drugs, membrane has been regarded as the crucial site for such a regulation and an important role for membrane ion exchangers has been suggested. The aim of this work was to elucidate whether the Na+/H+ antiporter is involved in the mechanism of regulation and circumvention of mdr and if 5-(N-ethyl-N-isopropyl) amiloride (EIPA), a selective inhibitor of the Na+/H+ exchanger, can modulate the functional expression of the mdr phenotype. The effect of EIPA on doxorubicin (DX) resistant cells (LoVo/DX) obtained from a human colon adenocarcinoma cell line (LoVo) was studied. EIPA at concentrations ranging from 10 to 50 mu M was able to increase the antibiotic cytotoxicity in the resistant Lovo/DX cells. The reversal of DX resistance paralleled an increase of the ability of the cells to accumulate the drug. Both drug loading and sensitivity to the inhibitory effect of DX on cell proliferation were restored by EIPA in a dose-dependent way. These results suggest a new mechanism of mdr reversal and indicate that amiloride and its derivatives may be useful in reversing DX resistance and in enhancing the clinical effectiveness of chemotherapeutics.

[Anomalies of coagulation and fibrinolytic activity in patients with chronic pulmonary thromboembolism]

INTRODUCTION

Haemostatic and fibrinolytic parameters were evaluated in patients with chronic pulmonary hypertension following pulmonary embolism (CPE). The diagnosis of CPE was based on lobar or segmental defects on perfusion lung scans and by pulmonary angiograms which showed complete or partial obstruction of main or segmentary lobar arteries.

METHODS

Antithrombin III (AT III), protein C, protein S, and lupus anticoagulant (LA) were assayed in 8 patients with CPE; in 6 out of 8 patients plasma fibrinolytic activity was assessed both under basal conditions and after venous stasis. The control group consisted of 4 normal subjects. Protein C and protein S antigens were assayed by an electrophoretic method. Protein C and protein S biological activities were assayed by a manual clotting system. AT III was assayed by chromogenic method. Fibrinolytic total activity was studied on fibrin plates, tPA and PAI-1 activities by chromogenic method; tPA and PAI-1 antigens by ELISA technique.

RESULTS

One patient out of 8 showed a protein C deficiency and 3 patients out of 8 were positive for a LA. All patients had a statistically significant reduction of plasma fibrinolytic activity (p < 0.001) and of tPA activity (p < 0.0005) after venous stasis as compared to the control group.

CONCLUSIONS

Our data show that significant haemostatic abnormalities may underlie this disease. In particular, a) an impairment of fibrinolytic plasma activity and low levels of plasminogen activator may be found, and b) the undiagnosed presence of a LA may be the cause of these thrombotic events. The meaning of these results needs further assessment.

Reduction of plasma fibrinolytic activity following high-dose cyclophosphamide is neutralized in vivo by GM-CSF administration

BACKGROUND

GM-CSF has broad clinical applicability as a potent myelopoietic stimulator. However, its function is not restricted to the myelopoietic system and several observations suggest that GM-CSF may interfere with the hemostatic balance. In order to assess whether GM-CSF has any influence on hemostasis, we evaluated some coagulative and fibrinolytic parameters in patients treated with GM-CSF following chemotherapy.

METHODS

Fibrinolytic activity (FA), fibrinogen and D-dimer were evaluated before and after high-dose cyclophosphamide in 6 patients additionally treated with GM-CSF and in 5 control patients; moreover, tissue plasminogen activator (tPA) was assayed in those treated with GM-CSF. Comparative in vitro analysis was performed on cultured endothelial cells before and after exposure to GM-CSF.

RESULTS

Control patients showed a significant decrease in plasma FA after chemotherapy compared to basal values (FA/mm2: 15.6 +/- 2.1 at day + 2 and 20.8 +/- 19 at day + 4 vs. 103.8 +/- 64.2 at day 0; p < 0.005); conversely, no FA reduction was observed in GM-CSF-treated subjects. In this latter group a marked increase in tPA antigen was seen, consistent with enhanced FA. No significant changes in plasma D-dimer and fibrinogen values were detected in the two groups. tPA, urokinase-type plasminogen activator, PAI-1 and procoagulant activity were evaluated in vitro on cultured human endothelial cells and found to be unchanged following GM-CSF addition.

CONCLUSIONS

The results demonstrate that high-dose chemotherapy may negatively influence plasma FA. This adverse side effect is neutralized by GM-CSF administration. The discrepancy found between in vitro and in vivo GM-CSF activity on hemostatic may be explained by in vivo GM-CSF stimulation of cell types other than endothelial cells.

Fibrinolytic imbalance in essential thrombocythemia: role of platelets

Thrombotic and hemorrhagic complications are frequent in patients with essential thrombocythemia (ET), a myeloproliferative syndrome with an increased number of circulating platelets. Since platelets are a physiological reservoir for the plasminogen activator inhibitor (PAI-1) contained in plasma, we evaluated plasma and platelet tissue plasminogen activator (tPA) and PAI-1 in 20 ET patients with and without thrombotic complications and in 13 control subjects. In ET patients with thrombotic complications there was a significantly greater platelet PAI-1 functional activity than in ET patients without thrombotic complications and in the control group (p < 0.05 and p < 0.025, respectively). Moreover, platelet tPA activity was significantly low in all ET patients (p < 0.001). This fibrinolytic imbalance (increased plasminogen inhibitor and lowered activator) might be a critical cofactor in the thrombotic complications in ET patients.

Lupus anticoagulant: interference with in vivo prostaglandin production and with platelet sensitivity to prostacyclin

The hypothesis has been made that inhibition of prostacyclin (PG12) production may play a role in the pathogenesis of thrombosis in patients with the lupus anticoagulant (LA), but so far no evidence of reduced PG12 levels in vivo has been produced. We have tested the plasma levels of PG12 and thromboxane A2 (TXA2) and the platelet sensitivity to PG12 in 14 patients with and without LA and in 14 healthy controls. No significant difference in the prostanoid basal levels was detected among the groups; however, in some patients PG12 increments seemed to parallel the clinical course of the disease. Platelet sensitivity to exogenous PG12 was significantly enhanced in the LA + patients and correlated with PG12 values. We suggest that in these subjects additional factors, other than reduced PG12, may predispose to thrombosis.

Antibody to hepatitis C virus after a vapour-heated factor VIII concentrate. The Study Group of the Fondazione dell'Emofilia

To evaluate whether or not clotting factor concentrates exposed to virucidal procedures transmitted hepatitis C, sera obtained in 1984-1986 from 27 previously untreated hemophiliacs infused with a vapour-heated factor VIII concentrate were tested retrospectively for the antibody to the hepatitis C virus (anti-HCV). A 2-year-old hemophiliac, negative for anti-HCV before administration of concentrate, seroconverted at week 12 and remained anti-HCV positive thereafter. Both his parents were anti-HCV negative and he had no other household contact. The patient had also become HBsAg positive at week 8 and had at the same time a marked elevation of alanine aminotransferase. His double infection with the hepatitis B and C viruses indicates that hot vapour was not completely effective in inactivating these viruses.

Role of Na+/H+ exchange in the granulocyte-macrophage colony-stimulating factor-dependent growth of a leukemic cell line

The growth of the human leukemia cell line AML-193 in a serum-free medium is strictly dependent on the presence of the cytokine granulocyte-macrophage colony-stimulating factor (GM-CSF), which is one of the major regulators of the myelomonocytic lineage. At present, little is known about the mechanisms by which this growth factor transduces the signal intracellularly. The results of this study demonstrate that GM-CSF needs the operation of a Na+/H+ exchanger, which is located in the plasma membrane of almost every vertebrate cell. In fact, the GM-CSF-dependent proliferation of AML-193 cells is strongly reduced in the presence of the amiloride analog EIPA, a specific inhibitor of the Na+/H+ exchanger. When acidified, AML-193 cells are able to recover the original pHi in a Na(+)-dependent and EIPA-inhibitable way; this demonstrates for the first time the presence of the Na+/H+ exchanger in these cells. Finally, GM-CSF, at doses superimposable to those needed for triggering proliferation, induces in AML-193 cells a sustained alkalinization, which is dependent on a operating Na+/H+ exchange, as it is inhibited by EIPA. These results suggest that GM-CSF, like other growth factors in other cell systems, exerts its mitogenic activity in AML-193 cells by inducing a Na+/H+ exchanger-mediated rise in pHi.

Paraproteinaemias and platelet aggregation: role of whole blood aggregometry

Whole blood and optical platelet aggregation were measured in normals and in patients with paraproteinaemias; extent of aggregation was correlated with paraprotein concentrations in patients and in normals after addition of different doses of paraproteins; threshold aggregating concentrations of several agonists were also determined in whole blood and in PRP from both groups of subjects. The results indicate that patients with macromolecular monoclonal component bear a "hyperaggregable" state which can be probably ascribed also to plasma hyperviscosity and which is better detected with the impedance aggregometer.

[Atracurium in general surgery]

The particular characteristics of atracurium in comparison with available relaxant agents are briefly analyzed. Afterwards the results of a clinical investigation regarding a group of 56 patients who underwent major abdominal surgery are referred to. The most important elements of this investigation involve: the priming technique, dosage variations of atracurium in respect to the two different administration techniques (further doses, continuous infusion), anticholinesterases need during neuromuscular block reverse and average neuromuscular recovery time without anticholinesterases.

No evidence of platelet activation during atrial pacing in subjects with stable angina

Platelet behaviour (activation) in ischemic heart disease (stable angina) during pacing-induced tachycardia was studied. ECG was recorded during the trial. Ischemic heart disease (IHD) subjects had 75% or more narrowing of the luminal diameter of a coronary artery, demonstrated by coronary angiography. Eight subjects needing cardiac catheterism because of supraventricular rhythm disturbances with no evidence of IHD were studied as controls. Beta-thromboglobulin (beta-tg) and platelet factor 4 (PF4) were studied as platelet activation markers; beta-tg and PF4 were evaluated before atrial pacing in peripheral venous blood and, by catheterism, before and at maximum pacing rate in coronary venous sinus (CVS) and in ascending aorta (AA). Catheterism and blood withdrawals were performed in order to reduce platelet activation in vivo. No significant difference in platelet activation between IHD patients and control group in peripheral venous blood were found. No trans-myocardial gradient neither in IHD subjects nor in controls were observed. In conclusion, no platelet activation in IHD patients during pacing-induced tachycardia could be observed.

Immunogenicity of a recombinant hepatitis B vaccine in hemophiliacs

Yeast-recombinant vaccines against hepatitis B virus (HBV) are now available, but there is no information about whether or not they are immunogenic in patients with hemophilia and other congenital bleeding disorders. Twenty micrograms of a recombinant vaccine expressing the adw serotype of the hepatitis B surface antigen (HBsAg) were given to 41 patients negative for HBV markers and again after 1 and 6 months. Ten percent of the vaccinees had anti-hepatitis B surface antibody (anti-HBs) responses, with titers of 10 mIU/ml or more, 1 month after the first dose of vaccine. The percentage of anti-HBs-positive patients increased to 54% after the second dose and to 98% after the third dose, with only one non-responder. Hence, the recombinant vaccine was immunogenic, with percentages of seroconversion and anti-HBs titers similar to those achieved with plasma-derived vaccines.

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 less than 1 and greater than 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.

Congenital deficiency of alpha-2-adrenoceptors on human platelets: description of two cases

The biochemistry and functionality of platelets from two related subjects (mother and son) with alpha-2-adrenoceptor-deficient platelets has been evaluated. Radioligand binding experiments with the specific alpha-2-adrenergic-receptor antagonist, 3H-yohimbine, showed a drastic reduction of alpha-2-adrenoceptors in platelets from both subjects in comparison with the control values. Electron microscopy studies revealed a normal morphology and a normal number of alpha granules and dense bodies. Levels of adenine nucleotides; 5-hydroxytryptamine; B-thromboglobulin; platelet-factor-4 and thromboxane A2 production were within normal limits. Platelet aggregation and 5-hydroxytryptamine production in response to adrenalin (at concentrations up to 50 microM) were absent, whereas ADP, AA, PAF, collagen and thrombin-induced aggregation, secretion, Ca++ flux and thromboxane A2 production were normal. The inhibitory effect caused by different concentrations of prostacyclin on Ca++ flux, aggregation, secretion and thromboxane A2 production of platelet functionally lacking of alpha-2-adrenoceptor was not distinguishable from control platelets and platelets preincubated with yohimbine.

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)

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.

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 (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)

In vivo platelet activation in lower limbs thrombophlebitis. A longitudinal study

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.

Exercise-induced changes of Factor VIII complex in healthy subjects and in type-I diabetics: relation between growth hormone and Von Willebrand Factor increments

This work aims to study the exercise-induced changes of Factor VIII Complex both in healthy subjects and in type I diabetics without vascular complications, and to investigate the possible relations between growth hormone and Von Willebrand's Factor response to exercise. Results show that maximal exercise performed by cycle ergometer causes a significant increment of the procoagulant subunit (VIII:C) and of Von Willebrand Factor (VIII:RiCoF) both in healthy controls and in type I diabetics, whereas a slight increment of Factor VIII-Related antigen (VIIIR:Ag) is observed only in diabetics. The shape of the mean GH response to exercise parallels the one of Von Willebrand's Factor: however, the presence of VIII:RiCoF increments also in GH non-responders supports the conclusion that growth hormone is not the only factor involved in the regulation of Von Willebrand's Factor exercise-induced increase.