Possible involvement of HtrA1 serine protease in the onset of osteoporotic bone extracellular matrix changes

High-temperature requirement A1 (HtrA1), a multidomain serine protease acting on Extracellular matrix (ECM) rearrangement, is also secreted by osteoblasts and osteoclasts. Recent and conflicting literature highlights HtrA1's role as a controller of bone remodeling, proposing it as a possible target for pathologies with unbalanced bone resorption, like Osteoporosis (OP). To add knowledge on this molecule function in bone physiopathology, here we compared HtrA1 distribution in the ECM of healthy (H) and OP bone tissue, also examining its localization in the sites of new bone formation. HtrA1 was homogeneously expressed in the mature bone ECM of H tissue showing a 55.6 ± 16.4% of the stained area, with a significant (p=0.0001) decrease in OP percentage stained area (21.1 ± 13.1). Moreover, HtrA1 was present in the endosteum and cells involved in osteogenesis, mainly in those "entrapped" in woven bone, whereas osteocytes in mature lamellar bone were negative. Based on our previous observation in OP tissue of a significantly increased expression of Decorin and Osteocalcin, both involved in bone mineralization and remodeling and equally substrates for HtrA1, we speculate that HtrA1 by controlling the proper amount of Decorin and Osteocalcin favors normal bone maturation and mineralization. Besides, we suggest that late-osteoblasts and pre-osteocytes secrete HtrA1 in the adjacent matrix whilst proceeding with their maturation and that HtrA1 expression is further modified during the remodeling from woven to the lamellar bone. Overall, our data suggest HtrA1 as a positive regulator of bone matrix formation and maturation: its reduced expression in mature OP bone, affecting protein content and distribution, could hamper correct bone remodeling and mineralization.

Indirect co-cultures of healthy mesenchymal stem cells restore the physiological phenotypical profile of psoriatic mesenchymal stem cells

Psoriasis microenvironment, characterized by an imbalance between T helper type 1 (Th1)/Th17 and Th2 cytokines and also influences the mesenchymal stem cells (MSCs) phenotypical profile. MSCs from healthy donors (H-MSCs) can exert a strong paracrine effect by secreting active soluble factors, able to modulate the inflammation in the microenvironment. To evaluate the influence of H-MSCs on MSCs from psoriatic patients (PsO-MSCs), H-MSCs and PsO-MSCs were isolated and characterized. Indirect co-culture of H-MSCs with PsO-MSCs was performed; effects on proliferation and expression of cytokines linked to Th1/Th17 and Th2 pathways were assayed before and after co-culture. The results show that before co-culture, proliferation of PsO-MSCs was significantly higher than H-MSCs (P < 0·05) and the levels of secreted cytokines confirmed the imbalance of Th1/Th17 versus the Th2 axis. After co-culture of H-MSCs with PsO-MSCs, healthy MSCs seem to exert a 'positive' influence on PsO-MSCs, driving the inflammatory phenotypical profile of PsO-MSCs towards a physiological pattern. The proliferation rate decreased towards values nearer to those observed in H-MSCs and the secretion of the cytokines that mostly identified the inflammatory microenvironment that characterized psoriasis, such as interleukin (IL)-6, IL-12, IL-13, IL-17A, tumour necrosis factor (TNF)-α and granulocyte-macrophage colony-stimulating factor (G-CSF), is significantly lower in co-cultured PsO-MSCs than in individually cultured PSO-MSCs (P at least < 0·05). In conclusion, our preliminary results seem to provide an intriguing molecular explanation for the ever-increasing evidence of therapeutic efficacy of allogeneic MSCs infusion in psoriatic patients.

The Ovariectomised Sheep as a Model for Testing Biomaterials and Prosthetic Devices in Osteopenic Bone: A Preliminary Study on Iliac Crest Biopsies

A histomorphometric and ultrastructural evaluation on sheep iliac bone was performed. Six sheep were ovariectomised (OVX Group) and 6 were left intact (Sham-aged, Control Group). An iliac crest biopsy was performed randomly in 6 animals at the beginning of the study, then, in all the animals, after 12 and 24 months. A significant decrease in trabecular bone volume, trabecular thickness (p<0.0005) and cell volume (p<0.005) was observed in OVX animals. A modest decrease in trabecular number and osteoid thickness together with an increase in trabecular separation were observed in OVX animals at 12 and 24 months. The osteoid volume showed a significant difference (p<0.05) between the groups. In OVX animals, at 12 months, Scanning Electron Microscopy revealed an enlargement of the trabecular space and a progressive replacement of bone matrix with adipose tissue. These signs were accentuated at 24 months.

In conclusion, OVX sheep showed a loss of trabecular bone starting at 12 months after ovariectomy. The developed osteopenic state may be considered as a useful tool when doing research on biomaterial osteointegration. (Int J Artif Organs 2000; 23: 275–81)

Fibroblast proliferation over dialysis membrane: an experimental model for “tissue” biocompatibility evaluation

The present study reports on a biological model based on fibroblast proliferation applied to 3 different types of flat-plate dialysis membrane, in order to ascertain whether the artificial materials currently used in hemodialysis cause in vitro cellular proliferation. The study plan we followed involved plate membrane isolation from non-used dialyzers and used dialyzers, observed through scanning electron microscopy (SEM) both before and after testing with human fibroblasts by means of cell culture. Fibroblast growth was assessed by phase contrast light microscopy examination and cytometric DNA content evaluation. Our investigations proved that the artificial materials we considered interact with fibroblast cultures. Noticeable proliferative response was observed both after contact with unused material and on mediation by the protein layer absorbed on the membrane surface at the end of dialysis sessions. In this last case fibroblast proliferative activity appeared higher than that observed with unused membranes, showing that the soluble molecules entrapped in the protein layer appeared able to exert a biological activity even in in vitro tests

Osteoinduction by Chitosan-Complexed BMP: Morpho-Structural Responses in an Osteoporotic Model

Bone quality is the result of a complex relationship between bone mass, bone structure, and mechanical characteristics of these individual components. The mass of bone tissue is affected by nutritional factors and other causes, such as bone growth factors like bone morphogenetic proteins (BMPs). Since chitosans promote ordered regeneration of soft tissue and osteoinduction, an osteoporotic model was studied to evaluate the pattern of bone regeneration in the presence of BMP linked to chitosan. BMP was released from the chitosan matrix as a consequence of chitosan biodegradation. Our data show that the association of BMP with chitosan seemed to improve the bone tissue regeneration in a surgical bone defect. This result provides validity to biochemical approaches for therapeutical correction of afflictions in the elderly, such as osteoporosis.

Experimental Wound Dressing by Heterologous Collagen: A Morphological-Quantitative Approach

The use of heterologous collagen in skin repair processes has proved to be an efficacious approach for the reconstitution of injured tissue. A morphological and quantitative evaluation of the reactive and reparative ca pacity of injured tissue treated either with conventional medications or with heterologous collagen (Condress) in the form of sponges was carried out. We have analyzed experimental surgical lesions on an animal model and evalu ated the repair processes of the lesions, including the excision of the cutaneous and subcutaneous tissue. The heterologous collagen sponges provided biologi cal support to obtain healed skin of better quality. Tissue lesions healed more rapidly, thus reducing the risk of recurrence. This experimental study provides morphological and structural data for further investigation.

Evaluation of Some Microenvironmental Inflences on the Regenerative Mechanisms of the Periodontium: An in Vitro Study

Studies have demonstrated the chemotactic response of periodontal ligament cells to a wide range of matrix molecules and growth factors, suggesting a therapeutic role for the latter in tissue lesion restoration. Impaired human gingival and periodontal ligament fibroblasts from adult donors were stimulated in vitro with growth factors or grown on a biosynthetic tissue-guiding membrane in the presence of tetracycline (minocycline) to assess the effects of these molecules on cell proliferation and tolerance to the drug. The results suggest that techniques involving tissue-guiding membranes and growth factors associated with inhibitors of collagenases constitute a promising biological-like way of restoring the delicate equilibrium disrupted by periodontal disease.

Dynamic Co-Seeding of Osteoblast and Endothelial Cells on 3D Polycaprolactone Scaffolds for Enhanced Bone Tissue Engineering

Tissue engineered scaffolds must have an organized and repeatable microstructure which enables cells to assemble in an ordered matrix that allows adequate nutriental perfusion. In this work, to evaluate the reciprocal cell interactions of endothelial and osteoblast-like cells, human osteoblast-like cells (MG63) and Human Umbilical Vein Endothelial Cells (HUVEC) were co-seeded onto 3D geometrically controlled porous poly(ε-caprolactone) (PCL) and cultured by means of a rotary cell culture system (RCCS-4DQ). In our dynamic co-culture system, the lack of significant enhancement of osteoblast ALP activity and ECM production indicated that the microgravity conditions of the rotary system affected the cells by favoring their proliferation and cellular cross-talk. These results emphasize how osteoblasts increase endothelial cell proliferate and endothelial cells amplify the growth of osteoblasts but decrease their differentiation. This dynamic seeding of osteoblasts and endothelial cells onto a 3D polymeric scaffold may represent a unique approach for studying the mechanisms of interaction of endothelial and osteoblast cells as well as achieve a functional hybrid in which angiogenesis, furnished by neo-vascular organization of endothelial cells may further support osteoblasts growth. Furthermore, this in vitro model may be useful in examining the applicability of novel material structures for tissue engineering.

Biocompatibility and osseointegration in osteoporotic bone

We implanted nails made of titanium (Ti6Al4V) and of two types of glass ceramic material (RKKP and AP40) into healthy and osteopenic rats. After two months, a histomorphometric analysis was performed and the affinity index calculated. In addition, osteoblasts from normal and osteopenic bone were cultured and the biomaterials were evaluated in vitro. In normal bone the rate of osseointegration was similar for all materials tested (p < 0.5) while in osteopenic bone AP40 did not osseointegrate (p < 0.0005). In vitro, no differences were observed for all biomaterials when cultured in normal bone-derived cells whereas in osteopenic-bone-derived cells there was a significant difference in some of the tested parameters when using AP40. Our findings suggest that osteopenic models may be used in vivo in the preclinical evaluation of orthopaedic biomaterials. We suggest that primary cell cultures from pathological models could be used as an experimental model in vitro.

The effect of osteopenia on the osteointegration of different biomaterials: histomorphometric study in rats

The osteointegration of Hydroxyapatite (HA), Titanium (Ti-6Al-4V: Ti), Zirconia (ZrO2), Alumina (Al2O3) and 2 biological glasses (AP40 and RKKP) was comparatively investigated in normal and osteopenic rats by means of histomorphometry. Thirty-six Sprague Dawley female rats were left intact (Group C) while 36 were ovariectomized (Group OVX). Group C and OVX were further divided into 6 subgroups. After 16 weeks all animals were submitted to the femoral implant of nails made of the above-mentioned materials. Eight weeks after implantation the animals were euthanized, the femurs were harvested for histomorphometric analysis. The data showed that: (1) all the tested materials were biocompatible in vitro; (2) no significant differences existed in Affinity Index (AI) of Group C; and (3) results from paired comparison applied to the AI showed significant differences among the Groups C and OVX. The AI did not significantly change among intact groups, while it significantly decreased when some materials were implanted in OVX subgroups (AP40, ZrO2 and Ti-6Al-4V: p < 0.0005, p < 0.05 and p < 0.01). It is confirmed that bone mineral density is a strong predictor of the osteointegration of an orthopedic implant and that the use of pathological animal models is necessary to completely characterize biomaterials.

Bioactivity of chitosan in dentistry. Preliminary data on chitosan-based cements

BACKGROUND

The chemical association of chitosan with inorganic salts, such as calcium phosphate, finds a promising application in dentistry as room-temperature self-hardening cement. We present the physical, chemical and crystallographic characterization of newly-developed cements made of 1) calcium-phosphate and a chitosan gel obtained by acetic acid treatment, and 2) calcium phosphate and a chitosan gel obtained by ascorbic acid treatment. Both cements are self-hardening at room temperature.

METHODS

The cements were characterized by X-ray diffractography, scanning electron microscopy and fluorine-selective electrode analysis.

RESULTS

The chitosan-hydroxyapatite cements had hardness comparable to spongy bone and above that of PMMA.

CONCLUSIONS

The cements are promising for application in endodontics and restorative dentistry.

Bioactivity modulation of bioactive materials in view of their application in osteoporotic patients

The application of bioactive ceramic coatings to prostheses confers strength to a material (ceramic or biological glass) that exerts beneficial effects on bone-tissue growth but that itself lacks the toughness and stability required of an implant device. The rate of bioactivity is related to the chemical reactivity of the material and causes interface dissolution, precipitation and ion-exchange reactions. Ceramics may differ in sintering temperature and thus exhibit differences in their in vitro dissolution features and in vivo performance. To test these effects, in vitro and in vivo studies were carried out on two biocompatible biological glasses and a ceramic of proven bioactivity in view of their potential utilization as covering materials. In addition, a modified chitosan was adsorbed on the surface of a series of hydroxyapatite (HA) samples. Human fibroblasts and/or osteoblasts were used for the in vitro tests, and normal (INT) and osteoporotic (OVX) rats, normal rabbits and sheep for the in vivo studies. Similar chemical changes were observed in both glasses, suggesting that these materials underwent modifications directly dependent on their biological environment. The in vivo tests point to the possibility of improving the bioactivity of ceramic substrates with chitosan. However, the different behaviour of the materials in vitro and in vivo suggests that these tests should be conducted in parallel.

Biomaterials for orthopedic surgery in osteoporotic bone: a comparative study in osteopenic rats

To evaluate orthopedic devices in pathological bone, an experimental study was performed by implanting Titanium (Ti) and Hydroxyapatite (HA) rods in normal and osteopenic bone. Twenty-four rats were used: 12 were left intact (

CONTROL

C) while the other 12 were ovariectomized (OVX). After 4 months all the animals were submitted to the implant of Ti or HA in the left femoral condyle (Ti-C, HA-C, Ti-OVX, HA-OVX). Two months later the animals were sacrificed for histomorphometric, ultrastructural and microanalytic studies. Our results show a significant difference between the Affinity Index (A.I.) of HA-C and Ti-C (77.0 +/- 7.4 vs 61.2 +/- 9.7) (p < 0.05). No significant differences were observed between the osteointegration of Ti-C and Ti-OVX (61.2 +/- 9.7 vs 48.2 +/- 6.7). Significant differences also exist between the osteointegration of HA-C and HA-OVX (77.0 +/- 7.4 vs 57.6 +/- 11.5) (p < 0.01). Microanalysis shows some modifications in Sulphur (S) concentration at the bone/biomaterial interface of the Ti-OVX group. Therefore our results confirmed the importance of biomaterials characteristics and of bone quality in osteointegration processes.

Structural features of latex gloves in dental practice

The aim of this study was to define from a morpho-structural point of view, using scanning electron microscopy, the features of various types of disposable latex gloves commonly used in Italian dental practice (Biogel D, Trend, Pagni, J&J, Latechnics, Pehasoft, Bantex). None of the brands examined was free from morphological flaws; however, while in some of these only slight depressions were found (Biogel D, Trend), in others (Latechnics, Bantex) there was a marked lack of homogeneity in the latex structure or real holes (Pehasoft). This study emphasizes the current difficulties faced by dentists in the search for safe working conditions.

Fibroblast proliferation over dialysis membrane: an experimental model for "tissue" biocompatibility evaluation

The present study reports on a biological model based on fibroblast proliferation applied to 3 different types of flat-plate dialysis membrane, in order to ascertain whether the artificial materials currently used in hemodialysis cause in vitro cellular proliferation. The study plan we followed involved plate membrane isolation from non-used dialyzers and used dialyzers, observed through scanning electron microscopy (SEM) both before and after testing with human fibroblasts by means of cell culture. Fibroblast growth was assessed by phase contrast light microscopy examination and cytometric DNA content evaluation. Our investigations proved that the artificial materials we considered interact with fibroblast cultures. Noticeable proliferative response was observed both after contact with unused material and on mediation by the protein layer absorbed on the membrane surface at the end of dialysis sessions. In this last case fibroblast proliferative activity appeared higher than that observed with unused membranes, showing that the soluble molecules entrapped in the protein layer appeared able to exert a biological activity even in vitro tests.

A biochemical-morphological study on microvillus plasma membrane development

The microvillus plasma membrane of the human placental syncytiotrophoblast at term has been extensively studied, while little is known about the characteristics of its development. The aim of the present work was to compare functional and structural properties of this membrane at early and term gestational age. Ten normal term placentas (40 weeks) and ten placentas at 10 weeks of gestational age were studied. The Na+/K+-ATPase activity is significantly decreased in the syncytiotrophoblast plasma membrane obtained from term placentas as compared to the early ones, with significant variation of maximum velocity (Vmax). The microviscosity, evaluated by the P parameter of DPH and Sn parameters of 5- and 16-NS, is increased in the term placentas compared to the early placentas. This alteration is accompanied by an increased cholesterol to phospholipids ratio in term placentas, while there is a decreased unsaturated to saturated fatty acid ratio. As follows from morphological studies, an increased mean diameter in the E face was observed in the term placenta with respect to the early placenta. The distribution factor DF, which indicates the particle aggregation state, decreased in the E face in the term placenta as compared to the early one. The present biochemical morphological study shows that a deep modification of the membrane is at the basis of the syncytiotrophoblast plasma membrane development.

Antithrombin III infusion suppresses the hypercoagulable state in adult acute lymphoblastic leukaemia patients treated with a low dose of Escherichia coli L-asparaginase. A GIMEMA study

Thrombotic events have been reported in acute lymphoblastic leukaemia patients, especially during or after L-asparaginase administration. A so-called L-asparaginase associated coagulopathy has been well recognized, being characterized by a hypercoagulable state (decrease of antithrombin III, plasminogen, protein C, protein S and increase of prothrombin fragment F1 + 2, thrombin-antithrombin complexes and fibrinopeptide A). The aim of this study was to determine whether the supplementation of antithrombin III (AT-III) concentrates could improve the L-asparaginase associated coagulopathy, thereby blocking the activation of the haemostatic system. In 25 adult patients with acute lymphoblastic leukaemia (M 19, F6, mean age 34 years) antithrombin III (AT-III) concentrates were administered at daily doses of 50 U/kg for 10 consecutive days from the beginning of L-asparaginase therapy (6,000 U/m2/day s.c. for 7 days), given according to the GIMEMA ALL 0288 trial. A marked increase of antithrombin III was recorded on days IV-VIII-XI (P < 0.001). No changes in protein C, protein S, plasminogen, alpha 2-antiplasmin, factor VII and platelet count were observed and there was no increase in markers of hypercoagulability. There was no evidence of disseminated intravascular coagulation. In conclusion, AT-III concentrate supplementation during L-asparaginase therapy, by the achievement of high levels of antithrombin III, is associated with a lack of activation of the haemostatic system and appears to overcome the complex coagulopathy associated with L-asparaginase.

Platelet abnormalities in idiopathic myelofibrosis: functional, biochemical and immunomorphological correlations

BACKGROUND

An extensive study of platelet function was performed on 18 consecutive patients affected by idiopathic myelofibrosis (IM).

MATERIALS AND METHODS

Clinical hematological and morphofunctional parameters were studied in IM patients and control subjects. Platelet tests, ultrastructural data, immunocytochemical von Willebrand factor detection, freeze fracturing results and free cytosolic calcium level were evaluated.

RESULTS

Bleeding time was frequently found to be prolonged, but it never reached levels which could give any cause for concern. Aggregation by ADP, collagen and epinephrine was always altered, sometimes profoundly; on the contrary, agglutination by ristocetin was almost always normal, albeit occasionally increased. Plasma beta-TG and PF4 levels were found to be elevated in 11 and 12 patients, respectively. This indicated an abnormal release from platelet alpha-granules. Depletion of alpha-granules was also confirmed by the intraplatelet von Willebrand factor (vWF) labelling with colloidal gold particles bound to polyclonal antibodies against human vWF. In fact: 1) the number of positive alpha-granules/microm2 and per single platelet was reduced; 2) the intensity of the immunocytochemical reaction for single positive alpha-granules and for each platelet was significantly reduced. Freeze-fracturing studies showed an increase in the number of intra-membrane particles (IMP) on the P face of the platelet membrane with respect to normal platelets preincubated with ADP. However, no differences in their distribution or diameter were observed. High concentrations of free cytosolic calcium were always found and Ca++ ATPase activity was increased. Conversely, Na+/K+ ATPase activity was always reduced.

CONCLUSIONS

We can hypothesize that the platelet membrane is altered in IM, resulting in facilitated activation, even by subliminal stimuli, and that this continuous platelet activation ultimately leads to alpha-granule depletion.

Osteoconductive properties of methylpyrrolidinone chitosan in an animal model

Bone defects were surgically produced in the tibiae of rabbits and medicated with freeze-dried methylpyrrolidinone chitosan. Histological observations 60 d after surgery showed a considerable presence of neoformed bone tissue, as opposed to controls, originating from the pre-existing bone as well as from the periosteum. The cationic nature and the chelating ability of the methylpyrrolidinone chitosan apparently favoured mineralization. Endosteal-periosteal and bone marrow osteoblast-like precursors, stimulated by growth factors entrapped in the coagulum-polysaccharide mixture, gave rise to intramembranous bone formation. The ultrastructural examination evidenced that bone osteoid was followed by mineralization of the tissue.

Hypercoagulability in patients undergoing autologous or allogeneic BMT for hematological malignancies

Severe thrombotic alterations, such as veno-occlusive disease of the liver, may occur in the early phase following high-dose chemoradiotherapy and BMT. In this study, performed in patients with hematological malignancies subjected to allogeneic (10 cases) and autologous (20 cases) BMT, we have monitored laboratory hemostatic parameters to better understand the pathogenetic mechanism of thrombosis and particularly of veno-occlusive disease. Prothrombin time, activated partial thromboplastin time, plasma fibrinogen, markers of hypercoagulability (thrombin-antithrombin complex and prothrombin fragment F1+2); natural anticoagulants (protein C, protein S and antithrombin) together with fibrinolytic parameters (plasminogen, alpha 2-antiplasmin, tissue-plasminogen activator, plasminogen activator inhibitor and D-dimer) were assessed before transplant, on day 0 and weekly for 1 month thereafter. A hypercoagulability state, not related to an impairment of the anticoagulant and fibrinolytic systems, was documented before and after autologous and allogeneic transplant. Two patients developed veno-occlusive disease: they did not show any difference from the other patients before transplant while they presented a decrease of the natural anticoagulants along with altered fibrinolytic parameters only at the clinical onset of veno-occlusive disease. In conclusion, in this study a state of marked hypercoagulability was documented in BMT patients and the hemostatic laboratory parameters evaluated were not able to predict the occurrence of the thrombotic complications.

Increased serum levels of transforming growth factor beta-1 in patients affected by thrombotic thrombocytopenic purpura (TTP): its implications on bone marrow haematopoiesis

In this study we evaluated the effect of serum collected from seven thrombotic thrombocytopenic purpura (TTP) patients, either in the acute phase of the disease or in clinical remission, on the in vitro growth of bone marrow haematopoietic progenitor cells, obtained from the same TTP patients in clinical remission and from normal donors. The addition to the cultures of autologous sera collected from TTP patients in acute phase of the disease showed a clear-cut dose-dependent inhibition of immature haematopoietic progenitor cells (BFU-E, CFU-meg and 14th day CFU-GM). On the other hand, no inhibitory effects were observed on more mature 7th day CFU-GM. Interestingly, also sera collected from TTP patients in clinical remission still maintained some inhibitory activity on the growth of immature progenitor cells. A similar inhibitory activity was noticed when TTP sera were tested on normal bone marrow haematopoietic progenitor cells. Such inhibitory activity was significantly reduced in blocking experiments by the addition of a polyclonal neutralizing anti-TGF-beta 1 antibody and the presence of increased levels of both bioactive and latent TGF-beta 1 in TTP sera was confirmed in a bioassay on CCL64 cells. These data contribute to explain the lack of a clear compensatory haematopoiesis observed in some patients with active TTP and add further evidence to the notion of the existence of a state of latent platelet activation in TTP patients in clinical remission.

Recombinant alpha-interferon 2b in the treatment of HIV-related thrombocytopenia

OBJECTIVE

To assess the efficacy and the mechanism of action of alpha-interferon (alpha-IFN) in the treatment of HIV-related thrombocytopenia.

METHODS

Thirteen HIV-positive subjects [nine men and four women with severe thrombocytopenia (platelets, < or = 30 x 10(9)/l)] were treated with alpha-IFN 2b alone at a dose of 3 x 10(6) U three times a week for 5 weeks. Haematological parameters, platelet kinetic and bone-marrow myeloid progenitor cultures [megakaryocyte colony-forming units (CFU-MK); granulocyte macrophage CFU (CFU-GM) and erythroid burst-forming units (BFU-E)] were evaluated before and after treatment in responsive subjects.

RESULTS

Seven out of 13 subjects showed a partial response (platelets, 50-149 x 10(9)/l) after alpha-IFN 2b therapy. Platelet survival as evaluated by 111In-oxine significantly increased, while platelet turnover showed a slight but not statistically significant increase after treatment. The growth of bone-marrow myeloid progenitor cells decreased after alpha-IFN 2b therapy, again without statistical significance.

CONCLUSION

alpha-IFN 2b may increase the platelet count in HIV-positive subjects with severe symptomatic thrombocytopenia by prolonging platelet survival. The immunomodulatory and antiviral action of this drug may be responsible for prolonged platelet survival.

Supranormal antithrombin III levels induced by concentrate administration are ineffective in quenching thrombin generation in acute promyelocytic leukemia

Coagulation abnormalities occurring in patients with acute promyelocytic leukemia (APL) are partially corrected by heparin administration. This study was undertaken to verify if "supra-normal" levels of antithrombin III (AT-III) are similarly able to quench intravascular thrombin generation triggered by APL cells. Eight patients with APL were randomly assigned to receive either 50 U/kg (Group A) or 100 U/kg (Group B) of an AT-III concentrate, starting on the first day of chemotherapy and continuing for 7 days thereafter. Fibrinopeptide A (FPA), prothrombin fragment F1+2 and thrombin-AT III complexes, measured before and 15 minutes after each AT-III infusion, decreased significantly after each infusion, but the effect was minimal and short-lived, despite the achievement of post-infusion levels of AT-III activity well above 150% (Group A) or 200% (Group B). Small amounts of heparin were consistently detected in AT-III concentrates and post-infusion plasma samples. The short-lived quenching of thrombin generation after AT-III concentrate could be partially explained by the infusion of heparin, rather than by supranormal AT-III levels.

Evidence of a hypercoagulable state in patients with acute lymphoblastic leukemia treated with low dose of E. coli L-asparaginase: a GIMEMA study

Blood coagulation abnormalities induced by administration of E. coli L-asparaginase were investigated in 25 patients with acute lymphoblastic leukemia treated according to the GIMEMA ALL 0288 trial. Dosage of L-asparaginase was relatively low (6,000 U/m2/day for 7 days total dose 42,000 U/m2) as compared to the conventional dosages (120,000-140,000 U/m2 over 10-14 days). A significant decrease in fibronogen, plasminogen, alpha2-antiplasmin and antithrombin III was observed from day IV of L-asparaginase and it was maximum on day VIII, with return to the baseline levels on day XV. Protein C levels had only a borderline reduction, while no modification of protein S or factor VII was observed. Two of the patients investigated developed thrombosis. The presence of a prothrombotic state induced even by this low dosage of E. coli L-asparaginase was suggested by a significant increase of sensitive markers of hypercoagulability such as fibrinopeptide A, thrombin-antithrombin complexes, and prothrombin fragment F1 + 2.

In vitro inhibition of interferon alpha-2a antiproliferative activity by antibodies developed during treatment for essential thrombocythaemia

BACKGROUND

Various authors have reported the development of anti-interferon (IFN) antibodies following IFN-alpha treatment for haematological malignancies. So far the methods for detecting these antibodies have not considered the antiproliferative activity of this IFN, which is its most important property in anticancer therapy.

METHODS

In this in vitro study we evaluated the ability of anti-IFN alpha-2a neutralising antibodies to inhibit the antiproliferative activity of IFN alpha-2a and lymphoblastoid IFN alpha using megakaryocyte colony growth as the revelatory system. These antibodies were detected in two patients affected by essential thrombocythaemia (ET) who lost their haematological response to IFN alpha-2a, but responded to a subsequent treatment with lymphoblastoid IFN alpha.

RESULTS AND CONCLUSION

The results show that the inhibition of megakaryocyte colony growth induced by IFN alpha-2a was totally suppressed in the presence of the two ET patients' sera, whereas the inhibition induced by lymphoblastoid IFN alpha was not significantly affected. These in vitro data demonstrate the high specificity and activity of these antibodies on the antiproliferative effect of IFN alpha-2a.

Ascorbic acid for the treatment of chronic refractory idiopathic thrombocytopenic purpura (ITP)

We describe our experience with ascorbic acid in the treatment of chronic refractory ITP. Nine patients, 5 males and 4 females aged 27-74 years, 4 of whom were previously splenectomized, received the drug at a daily dose of 2 grams. After 2-12 months (median 4) of treatment, a partial response was observed in only one patient, while no response was registered in the other eight. Our data, analyzed together with those of the literature, allow us to conclude that ascorbic acid may not be considered a drug of interest in the treatment of chronic refractory ITP.

A regimen for antithrombin III substitution in patients with acute lymphoblastic leukemia under treatment with L-asparaginase

BACKGROUND AND METHODS

Seventeen adult patients with acute lymphoblastic leukemia (ALL) treated with L-asparaginase (20,000 IU/m2 on six alternate days) were infused with antithrombin III (AT III) concentrates (Kybernin P, Behring). Substitution therapy was aimed at increasing the reduced AT III concentration usually found in these patients, since AT III deficiency is thought to be associated with an increased risk of thrombosis. Two schedules of AT III administration, different in dosage, timing and duration were evaluated. The first 7 patients (group A) received a fixed dose of 2,000 U every day for 6 times, starting with the second L-asparaginase (L-ase) infusion, independently of their plasma AT III levels. In the following 10 patients (group B), 20-25 U/Kg b.w. were administered daily for 7 times only when the plasma AT III level was lower than 60% with plasma fibrinogen higher than 100 mg/dl and platelet count higher than 50 x 10(9)/l, or when AT III was below 40%. Thirteen patients who received L-ase without AT III substitution served as controls.

RESULTS AND CONCLUSIONS

Both substitution regimens resulted in mean plasma AT III nadir values significantly (p less than 00.1) higher than in the controls. Our data suggest that, in ALL patients receiving L-ase according to the L20 protocol, satisfactory plasma AT III levels may be assured with infusions of 20-25 U/Kg b.w./day for 7-10 days, starting by day 2 of L-ase treatment.

Platelet function and interferon alpha-2a treatment in essential thrombocythaemia

The effects of interferon (IFN) alpha-2a treatment on platelet function were evaluated in 20 patients affected by essential thrombocythaemia (ET). Baseline data documented the well-known abnormalities of in vitro platelet aggregation and the constant presence of a delta-storage pool deficiency. The therapy in all patients reduced the platelet count, and in the majority of them caused a partial improvement of in vitro platelet aggregation. Although the mean intraplatelet ADP level improved during treatment, it always remained below the normal range documenting persistence of the delta-storage pool deficiency. The plasma beta-TG levels, which initially were high, significantly decreased during treatment, but the beta-TG ratio and the platelet beta-TG values always remained within the normal range--this suggests an absence of platelet activation either before or during therapy. Our results demonstrate that, despite significantly reducing the platelet count, IFN alpha-2a treatment only partially corrects the qualitative platelet abnormalities in ET.

The risk of developing disease for siblings of patients with insulin dependent diabetes mellitus

We analyzed the risk of developing insulin-dependent diabetes mellitus (IDDM) in 411 siblings of patients with IDDM. We found that siblings who had a positive test for antibodies against islet cells (ICA) at the time of diagnosis of the index case had a higher risk of developing IDDM than did those who had negative tests. However, of the ten siblings who developed IDDM, only four were positive at the initial testing. The period of time elapsing from a negative test at screening to a positive test at diagnosis varied but was less than one year in one child. Two of the ten siblings who developed IDDM had negative tests both at screening and at diagnosis. Amongst siblings who were negative at the initial screening, those in whom the index case was diagnosed at a young age had a higher risk of developing IDDM than did those in whom the index case was diagnosed at an older age. The age of the sibling at the time of screening, the sex of the sibling, and a positive family history (one which includes in addition to the index case one or more first-degree relatives with IDDM) did not confer increased risk. Our data suggest that screening for ICA will have to be done often and will have to be continued into adult life in order to identify the 70-80% of diabetics who will be positive at some time in the evolution of their disease.

Essential thrombocythemia: impaired regulation of megakaryocyte progenitors

In this paper, the in vitro growth of bone marrow early (megakaryocyte burst-forming units, BFU-meg) and late (megakaryocyte colony-forming units, CFU-meg) progenitors was evaluated in 18 essential thrombocythemia (ET) patients and 22 normal control subjects. BFU-meg clonality was demonstrated both in normal and ET bone marrows, cultivating these primitive progenitors at limiting dilutions in plasma clot assay: 1 to 7 BFU-meg/2.5 x 10(4) mononuclear non-adherent cells were observed, with a strong correlation in ET [r = 0.955 stimulated by recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF) plus recombinant human interleukin (rhIL) 3], as well as in normal controls (r = 0.969). In order to clearly elucidate the in vitro response of ET megakaryocyte (meg) progenitors to recombinant growth factors, the interference of accessory cells (i.e., monocytes, T lymphocytes, and natural killer cells) and human serum were avoided by performing experiments on CD34+ cells in a serum-free fibrin clot assay. The number of both early and late meg progenitors in ET was significantly increased in response to rhIL-3, rhIL-3 plus rhIL-6, and rhIL-3 plus rhGM-CSF, but not in response to rhGM-CSF alone. Furthermore, both meg progenitors were investigated for their response to rh transfer growth factor (TGF)-beta 1, tested at concentrations from 0.01 to 10 ng/ml. rhTGF-beta 1 was able to inhibit CFU-meg and BFU-meg in a dose-response manner normal, whereas ET CFU-meg appeared less sensitive to the lower doses investigated (p less than 0.05) and ET BFU-meg were slightly reduced in number only at the higher concentrations of rhTGF-beta 1 (p less than 0.01). Our data suggest that the increased thrombopoiesis in ET may depend on an increased sensitivity of meg progenitors to some of the physiological growth factors and to a disrupted sensitivity to at least one negative regulator of megakaryocytopoiesis. Since these abnormalities involve both meg progenitors, this can be considered a demonstration that the neoplastic event hits the most primitive hemopoietic progenitors.

Prompt plasma-exchange treatment and coma reversibility in two patients with thrombotic thrombocytopenic purpura

We report on the cases of two women with acute thrombotic thrombocytopenic purpura (TTP) whose clinical courses were characterized by the onset of a coma state. Prompt commencement of plasma-exchange (PE) treatment led to complete hematological and neurological remission, which can still be observed without any maintenance therapy. No CNS abnormalities were observed in either patient using brain CT and NMR scans.

L-asparaginase treatment reduces the anticoagulant potential of the protein C system without affecting vitamin K-dependent carboxylation

The changes in plasma levels of the vitamin K-dependent natural anticoagulants protein C (PC) and protein S (PS) and procoagulant factors II, IX and X were evaluated in 8 adult patients during treatment with L-asparaginase (L-ase i.v. 120,000 U/m2 over 10 days). PC anticoagulant activity and factor IX, X and II coagulant activity decreased proportionally to their half-lives to a nadir of 50-60% of pretreatment values after 2-5 L-ase infusions, suggesting that inhibition of protein synthesis rather than consumption is the main mechanism responsible for the observed changes. Free PS antigen levels declined at a rate similar to total PS antigen, reaching a nadir of 56% of pretreatment values after 3 L-ase infusions; however due to C4b-binding protein levels higher than total PS levels (p less than 0.05), they were constantly lower than the corresponding total PS antigen levels (0.05 less than p less than 0.001). This implicates that total PS antigen levels cannot be taken as an indicator of PS activity. No differences between the antigenic levels and the anticoagulant activities of PC and free PS could be observed suggesting that L-ase does not affect the mechanisms of vitamin K-dependent carboxylation of Gla-residues. The faster rate of decline of PC and PS activities relative to that of factor II may be responsible for the onset of an hypercoagulable state during the early phase of L-ase treatment.

Ticlopidine in the treatment of thrombotic thrombocytopenic purpura: report of two cases

The observation of two clinical cases make possible an evaluation of the potential therapeutic activity of platelet function inhibitors in thrombotic thrombocytopenic purpura (TTP). In particular, the clinical and hematological effects of ticlopidine (TC), employed alone in two TTP patients, are reported. The mechanism of action of this peculiar antiplatelet drug is mainly represented by the inhibition of fibrinogen binding on the platelet surface. In the first patient, a 45-year-old female in whom plasma-exchange (PE) and corticosteroids (C) led to a partial remission (platelets 80 x 10(9)/l), treatment with TC at a dose of 750 mg/day was carried out, and after 6 weeks a normal platelet count was observed. A complete remission was maintained for 31+ months, even after reduction of the TC dose to 250 mg/day. In the second patient, an 18-year-old female affected by relapsing TTP, a complete remission obtained with PE and C was maintained for 19 months in concomitance with TC treatment, started at a dose of 750 mg/day and lowered to 250 mg/day. After 11 months of treatment at this low dosage there was a relapse (platelets 20 x 10(9)/l), but the increase of the TC dose to 750 mg/day in a few weeks induced a complete remission again. These data, in accord with a few other recent preliminary reports, suggest that TC, even alone, may play an interesting role in the management of TTP patients.

Hypercoagulability during L-asparaginase treatment: the effect of antithrombin III supplementation in vivo

To evaluate the occurrence of hypercoagulability during treatment with L-asparaginase (L-ase), thrombin-antithrombin complex (TAT) and D-dimer levels in plasma were serially measured in 15 consecutive adult patients with acute lymphoblastic leukaemia or lymphoblastic lymphoma who had recently completed a chemotherapy cycle with cytosine arabinoside and methotrexate. The first eight patients (group A) received i.v. L-ase alone (20,000 U/m2 on alternate days over 10 d); the last seven patients (group B) received, in addition to L-ase, bolus injection of antithrombin concentrate (2000 U) on alternate days for a total of six administrations, beginning with the second L-ase infusion. Increased levels of TAT (P less than 0.05) and D-dimer (P less than 0.01) were observed prior to L-ase, possibly related to inflammation and cytolysis secondary to previous chemotherapy. In patients treated with L-ase alone, further elevation of TAT (P less than 0.05) and persistence of increased D-dimer were observed, associated with marked reduction of the anticoagulant activities of protein C, protein S and antithrombin III. At variance, in patients receiving antithrombin III supplementation there was no increase of TAT and a normalization of D-dimer levels occurred during L-ase treatment. In these patients, mean plasma antithrombin III activity was maintained at levels higher than 70% of normal throughout the treatment. The rate of decline of fibrinogen, factor IX, protein C and protein S was unaffected by antithrombin III supplementation, indicating that hypercoagulability has little if any relevance for the reduction of coagulation factors and inhibitors induced by L-ase treatment. The usefulness of antithrombin III concentrates in preventing thromboembolic complications in patients submitted to L-ase treatment remains to be determined.

Case-control study of IDDM

Insulin-dependent diabetes mellitus (IDDM) may be caused by a combination of genetic predisposition and environmental insults. However, there are few solid leads concerning human diabetogenic environmental agents. A case-control study was carried out to investigate the possible relationships between IDDM and various biological, chemical, and psychological factors. All 161 cases of IDDM among children aged 0-17 yr occurring in Montreal from 1983 to 1986 were included. The parent of each newly diagnosed diabetic subject was asked to provide the names of two of the child's friends or neighbors who would be age and sex matched to serve as controls. For those unable to do so, matched controls were selected from a hospital emergency room. Parents of cases and controls were interviewed concerning many factors. There was little or no difference between cases and controls with regard to parental smoking habits, exposure to pets, and consumption of meat products high in nitrosamines. In univariate analyses, there was some indication of elevated risk for children who had not been breast-fed, who attended day care or nursery before age 5 yr, who lived in a crowded household at age 3 yr, or who had a history of asthma or eczema, although in multivariate analyses the only variables that had any effect were crowding and day-care attendance. In univariate and multivariate analyses, there was high risk of IDDM among children who had experienced selected stressful life events during the 12 mo preceding onset of IDDM or who had exhibited symptoms of social or psychological dysfunction during that time.(ABSTRACT TRUNCATED AT 250 WORDS)

In vivo and in vitro inhibitory effect of alpha-interferon on megakaryocyte colony growth in essential thrombocythaemia

Megakaryocyte (MK) colony growth of bone marrow mononuclear non-adherent cells was evaluated in 28 patients with essential thrombocythaemia (ET) and in 26 normal controls. The number of MK-colony forming units (CFU-MK per 3 x 10(5) plated cells) was similar in ET (68 +/- 33) and in controls (63 +/- 37), independently of bone marrow accessory cells. On the contrary, the size of the MK colonies was significantly (P less than 0.01) greater in ET patients. Human recombinant alpha-interferon 2a (alpha-IFN), administered to 10 patients at a dose of 3 x 10(6) IU/d s.c. for 11 +/- 3 weeks, was capable of inducing a significant (P less than 0.01) decrease in the number (from 72 +/- 16 to 31 +/- 14) and size of bone marrow CFU-MK, together with a significant reduction of the platelet count (from 1031 +/- 325 to 378 +/- 75 x 10(9)/l). When added in vitro at time 0 to the culture dishes, alpha-IFN inhibited the CFU-MK growth of both normal and ET bone marrow samples, even at very low concentrations (1 and 10 IU/ml). This study demonstrates that alpha-IFN, both in vivo and in vitro, exerts an inhibitory effect on the growth of MK progenitors, which appears to correlate with the clinically documented antiproliferative effect of this cytokine.

Incidence of IDDM in Montreal by ethnic group and by social class and comparisons with ethnic groups living elsewhere

We examined the incidence of insulin-dependent diabetes mellitus (IDDM) among children aged 0-14 yr in Montreal by social class and by ethnic group from 1971 to 1985. There was a slightly higher risk in wealthier as opposed to poorer classes. This income gradient was more marked in younger than in older children. Children of French extraction had about two-thirds the risk of IDDM of children of other origins, mainly British and other European. This mimics the patterns of risk in Europe, where France is reported to have lower rates than does Britain and Scandinavia. The absolute levels of risks among French Canadian and Jewish Canadian children were about double those reported from France and Israel, respectively. These various results are compatible with the hypothesis that both genetic and environmental factors influence IDDM risk.

Impact of SMBG on control of diabetes as measured by HbA1. 3-yr survey of a juvenile IDDM clinic

Three hundred twelve diabetic children and adolescents were seen in our diabetic clinic and instructed to test their capillary blood glucose (CBG) twice daily and to use an algorithm to adjust their short-acting insulin. Of this group, 219 youngsters had a full 3-yr period of observation. At each clinic visit, blood was obtained for fasting blood glucose and HbA1 and, once a year, cholesterol and triglycerides were also measured. Patient and parent accuracy in measuring CBG was found to be adequate. The changes over time in HbA1 were nondifferential across age and sex, and there was no difference in the level of HbA1 between age and sex groups, the number of tests reported to have been done by the patients, the number of injections of insulin per day, or the serum cholesterol. There was a significant relationship between the HbA1 and the fasting blood glucose (P less than .001) measured by the laboratory as well as with the serum triglyceride (P less than .01). The failure to improve diabetic control, despite measures that would have been expected to do so, was believed to relate more to a lack of compliance than to a flaw in the therapeutic approach. It was interesting to note that the adolescent patients in the study were in no worse control than the younger children in the group. Although better technical skills are available today to manage diabetes, the psychosocial approach to patient motivation requires improvement.

The distribution of type I (insulin-dependent) diabetes mellitus by age, sex, secular trend, seasonality, time clusters, and space-time clusters: evidence from Montreal, 1971-1983

The etiology of insulin-dependent diabetes mellitus remains obscure. In an attempt to clarify some aspects of the epidemiology, including its compatibility with an acute infectious process, the authors undertook in-depth analyses of childhood cases accumulated in a population-based register in Montreal during the period from 1971-1983. Incidence rates increased with age until puberty, at which point they plateaued and decreased. There was no overall difference in incidence between males and females; however, the rate for females peaked approximately two years before the rate for males. While there was some variation over time, there was no evidence of a long-term trend, nor was the yearly variation impressive in magnitude. The findings further indicate that the disease is not characterized by explosive outbreaks. There was slight seasonality, with a 28% higher rate of onset in fall and winter than in spring and summer. There was some evidence of space-time clustering in 1971-1973, but not thereafter. Taken as a whole, these findings do not support the hypothesis that a significant portion of insulin-dependent diabetes is caused by an acute infectious process.

Intensified insulin therapy in the type I diabetic adolescent: a controlled trial

The effects of continuous subcutaneous insulin infusion (CSII), intensified conventional therapy (ICT), and a combination of CSII and ICT (CSII-ICT) on metabolic control were compared in a group of twenty type I diabetic adolescents who had previously failed to respond to twice-daily injections and home glucose monitoring. A marked improvement in control was observed when mean glycemia and glycosylated hemoglobin A1 (HbA1) were compared with conventional therapy (CT). In the course of CSII, a lower HbA1 (P less than 0.05) and mean capillary blood glucose (CBG) (P less than 0.04) were observed than during ICT and CSII-ICT. Acceptability of CSII was greater than that of ICT and CSII-ICT, with 50% of the patients opting for this therapy at the end of the 1-yr trial. The marked improvement of control observed under CSII for the group as a whole was maintained after 6 mo of completion of the study. Thus, it appears that in type I diabetic adolescents CSII is more effective and acceptable than ICT and CSII-ICT.

Feasibility of strict diabetes control in insulin-dependent diabetic adolescents

Nineteen insulin-dependent diabetic adolescents who had poor control on twice daily injections and home glucose monitoring participated in a study assessing the feasibility of improved control. Using a randomized crossover protocol, we examined the relative efficacy of continuous subcutaneous insulin infusion and of intensive conventional therapy with three or four daily injections of insulin. Both therapies were regulated with home glucose monitoring. A marked improvement in control with both therapies was observed when mean blood glucose and glycosylated hemoglobin A1 were compared with conventional therapy. However, pump therapy resulted in significantly lower HbA1 than intensive therapy (P less than 0.05), despite a significantly lower total insulin dose (P less than 0.01). We conclude that in adolescents with type I diabetes, continuous subcutaneous insulin infusion is more effective in achieving improvement of diabetes control than is intensive conventional therapy in the outpatient setting.