Monte Verde: seaweed, food, medicine, and the peopling of South America

The identification of human artifacts at the early archaeological site of Monte Verde in southern Chile has raised questions of when and how people reached the tip of South America without leaving much other evidence in the New World. Remains of nine species of marine algae were recovered from hearths and other features at Monte Verde II, an upper occupational layer, and were directly dated between 14,220 and 13,980 calendar years before the present ( approximately 12,310 and 12,290 carbon-14 years ago). These findings support the archaeological interpretation of the site and indicate that the site's inhabitants used seaweed from distant beaches and estuarine environments for food and medicine. These data are consistent with the ideas that an early settlement of South America was along the Pacific coast and that seaweeds were important to the diet and health of early humans in the Americas.

Platelets interact with tissue factor immobilized on surfaces: effects of shear rate

BACKGROUND

While procoagulant activities of Tissue Factor (TF) have been widely investigated, its possible pro-adhesive properties towards platelets have not been studied in detail.

MATERIAL AND METHODS

We explored the interaction of platelets with human Tissue Factor (hTF) firmly adsorbed on a synthetic surface of polyvinilidene difluoride (PVDF) using different shear rates. For studies at 250 and 600 s(-1), TF firmly adsorbed was exposed to flowing anticoagulated blood in flat perfusion devices. Deposition of platelets and fibrin were evaluated by morphometric, immunocytochemical and ultrastructural methods. Prothrombin fragment 1 + 2 (F1 + 2) levels were also measured. Experiments at 5000 s(-1), were performed on the Platelet Function Analyzer (PFA-100) with experimental cartridges with collagen (COL) or collagen-hTF (COL + TF). Haemostatic effect of recombinant activated FVIIa (rFVIIa) was assessed in the same experimental settings.

RESULTS

Platelet deposition on hTF reached 19.8 +/- 1.3% and 26.1 +/- 3.4% of the total surface, at 250 and 600 s(-1), respectively. Fibrin formation was significantly higher at 250 s(-1) than at 600 s(-1) (P < 0.05). The addition of rFVIIa did not influence platelet deposition but raised fibrin formation and thrombin generation at both shear rates (P < 0.05). At 5000 s(-1), closure times (CT) in the PFA-100 were significantly shortened in the presence of hTF (154.09 +/- 14.69 s vs. 191.45 +/- 16.09 s COL alone; P < 0.05). Addition of rFVIIa did not cause a further reduction of CT.

CONCLUSIONS

Our studies demonstrate that hTF is an adhesive substrate for platelets and suggest that the von Willebrand factor could mediate these interactions. At low and intermediate shear rates, rFVIIa enhanced the procoagulant action of hTF, but this effect was not observed at very high shear rates.

AG-013736, a novel VEGF receptor and PDGF receptor inhibitor with potent activity against human bladder carcinoma in vitro and in vivo

13109

The receptors for vascular endothelial growth factor and platelet-derived growth factor (VEGFR-2 and PDGFR) play essential and complementary roles in angiogenesis, and combined inhibition of these receptors may therefore result in potent antitumor activity in vivo. Here we characterized the effects of a small molecule tyrosine kinase inhibitor AG-013736 (Pfizer) in HUVEC and human bladder cancer cells. Previously, AG-013736 was reported to inhibit VEGFRs with picomolar potency and PDGFRs with nanomolar activity. All of the cell lines examined displayed cell surface VEGFR-2 and PDGFR α and β expression as measured by flow cytometry. Low nanomolar concentrations of AG-013736 blocked the HUVEC cell proliferation with inhibition of VEGF receptor 2 and PDGF receptor phosphorylation. AG-013736 caused regression of established subcutaneous human bladder cancer xenografts, effects that were associated with inhibition of VEGFR-2 and PDGFR β phosphorylation but not EGFR phosphorylation and reduction in tumor microvessel densities (MVDs). Our results demonstrate that AG-013736 has substantial anti-angiogenesis activity in preclinical models of human bladder cancer, which warrants further exploration either alone or with the combination of other pre-clinical drugs in bladder cancer treatment.

No significant financial relationships to disclose.

Pilot study of capecitabine combined with celecoxib (CapCel) as second-line treatment for advanced pancreatic (P) and biliary tree (BT) cancer

14055

Background: COX-2 is overexpressed during cancer progression in several solid tumors, including P and BT, and constitutes an attractive therapeutic target. Selective COX-2 inhibitors, such as celecoxib, have been successfully combined with fluoropyrimidine-based regimens, resulting in a lower-than-expected hematologic, GI, and skin toxicity rate. Methods: Advanced P or BT patients (pts), progressing after first-line treatment, were eligible for the study. Capecitabine was administered at 1000 mg/m2 b.i.d. on days 1–14 q3 weeks; celecoxib was administered at 200 mg b.i.d. continuously starting on day 1. PFS was the primary endpoint. ORR, toxicity, OS, clinical benefit (CB), and QoL were secondary endpoints. Assuming that a rate of PFS >15% at 3 mos would be considered of interest in this pt population, an accrual of 28 pts was planned according to the exact single-stage phase II design described by A’Herne. Results: To date, 25 pts have been accrued (M/F: 11/14; median age: 64 yrs, range 39–75; P/BT: 18/7; PS 0–1/2–3: 19/6). All pts completed at least 1 treatment cycle (median: 3, range 1–9). Twenty-three pts are currently evaluable for response: 1 PR and 1 MR (duration: 33 and 27+ wks) were observed, both in pts with P; 5 additional pts showed SD (duration: 10+, 21, 22+, 27, and 42 wks); the remaining 16 pts had PD. All pts and 83 cycles are evaluable for toxicity. Hematological toxicity was negligible; only 4 pts experienced G3 non-hematological toxicities: diarrhea (2 pts, 2 cycles), skin toxicity (1 pt, resolved with treatment delay), asthenia (1 pt, 2 cycles), and GI bleeding (1 pt, requiring treatment interruption after cycle 1). To date, 19 pts have progressed and 15 pts have died: median PFS is 11 wks (range 3–42) and median OS is 16 wks (range 4–54). Nineteen pts had elevated CA19.9 serum levels at baseline, which decreased of > 25% during treatment in 7 pts, remained stable in 3 pts, and increased in 9 pts. The evaluation of CB and QoL is ongoing. Conclusions: CapCel is a feasible and well-tolerated, fully oral, treatment regimen for advanced P and BT patients, which shows activity, albeit modest, even in a second-line setting. Further evaluation of this therapeutic strategy is warranted.

No significant financial relationships to disclose.

Incidence of brain metastases after first line chemotherapy in breast cancer patients treated with or without trastuzumab

10582

Background: Brain metastases during trastuzumab therapy have been frequently observed. Only a few studies have compared the risk of brain metastases in patients (pts) treated with or without trastuzumab. Methods: In our hospital, between Jun 2000 and September 2005, we conducted a retrospective study in 72 metastatic breast cancer pts treated with first-line mono-chemotherapy (CT) with paclitaxel or docetaxel or vinorelbine ± Trastuzumab (T). Results: Thirty-five pts with HER2 pos disease were treated with T associated with 1st line CT, while 37 pts (16 with HER2 positive tumor, 21 HER2 negative) were not treated with T (NT). Ten HER2 pos NT pts subsequently received T. The median follow-up was 21 months (range1–129); the median age was 54 (range 32–82); the median treatment duration was 5 months (range 1–29). The incidence of recurrence (R), progressive disease in brain (BR), progression free survival (PFS) after first line CT, and overall survival (OS) were reported below: (see Table) Conclusions: This study showed that, after first line chemotherapy, the use of T did not affect the incidence of BR in HER2 pos metastatic breast cancer pts. On the other hand, Her-2 neg seems to predict ‘per se‘ a lower incidence of cerebral spread of disease.

[Table: see text]

No significant financial relationships to disclose.

Current status of targeted agents in advanced pancreatic cancer (APC): A pooled analysis of 2,361 patients (pts) enrolled in six phase III trials

4126

Background: Molecular targeting of pathways that are deregulated in pancreatic cancer is a promising approach aimed at improving the dismal prognosis of APC pts. However, the clinical impact of novel “biological” drugs (ND) remains to be defined. Methods: All prospective phase III trials comparing single-agent Gemcitabine (G) with either a ND or a combination of ND and G (ND+G) were considered eligible. A pooled analysis was performed and event-based relative risk ratios (RR) with 95% CI were derived through both a fixed- and a random-effect model approach, exploring OS as the primary outcome and PFS and ORR as secondary outcomes. Heterogeneity between different trials was also taken into account. Results: Six trials involving 2361 pts were identified; ND tested included: FTI inhibitors (1 trial), MMP inhibitors (3 trials), EGFR inhibitors (1 trial), and anti-gastrin vaccine (1 trial). The analysis was conducted considering three different subgroups: 1) overall population (2361 patients, 6 trials), 2) ND+G vs G (1879 patients, 4 trials), and 3) ND vs G (482 patients, 2 trials). As shown in the table, no significant differences in either the primary outcome (OS) or the secondary outcome of PFS were observed in the overall population as well as in ND+G vs G trials, while a significant negative trend for ND was found in ND vs G trials with regard to both endpoints. Conversely the evaluation of the secondary endpoint of ORR significantly favored G in the overall population as well as in ND vs G trials, while a not significant negative trend for ND was observed in ND+G vs G trials. Conclusions: G remains the treatment of choice in APC pts. The ND tested, either alone or combined with G, do not seem to add any benefit over G. A better understanding of pancreatic cancer biology and further clinical evaluation of new agents and is needed to improve prognosis in APC pts.

[Table: see text]

No significant financial relationships to disclose.

Gemcitabine-based polychemotherapy for advanced pancreatic cancer (APC): Is it ready for prime time? A pooled analysis of 3,682 patients (pts) enrolled in 12 phase III trials

4118

Background: Since the introduction of gemcitabine (G), attempts have been made to develop G-based combination regimens to improve the dismal outcome of APC pts. Results of randomized trials, however, have been conflicting and single-agent G presently remains the standard of care for such pts. Methods: All prospective phase III trials comparing single-agent G with G-based polychemotherapy regimens (poly-G) were considered eligible. A pooled analysis was performed and event-based relative risk ratios (RR) with 95% CI were derived through both a fixed- and a random-effect model approach, exploring OS as the primary outcome and PFS and ORR as secondary outcomes. Heterogeneity between different trials was also taken into account. Results: Twelve trials involving 3682 pts were identified. The analysis was conducted considering three different subgroups: 1) overall population (3682 patients, 12 trials), 2) platinum-containing poly-G (PG) vs G (768 pts, 5 trials), and 3) fluoropyrimidine-containing poly-G (FG) vs G (1640 pts, 4 trials). As shown in the table, no significant differences in the primary outcome (OS) were observed in any of the three groups analyzed. Conversely, a significant advantage for poly-G was evident with regard to both PFS and ORR in the overall population as well as in the PG vs G subgroup, although with some heterogeneity. A heterogeneous non-significant trend towards a better PFS and ORR outcome was also observed in the FG vs G subgroup. Conclusions: Single-agent G remains the treatment of choice in APC pts. However, the addition of platinum compounds to G appears to significantly improve PFS and ORR, possibly justifying the use of platinum-based poly-G in younger and fit patients.

[Table: see text]

No significant financial relationships to disclose.

Atomic force microscopy measurements of topography and friction on dotriacontane films adsorbed on a SiO2 surface

We report comprehensive atomic force microscopy (AFM) measurements at room temperature of the nanoscale topography and lateral friction on the surface of thin solid films of an intermediate-length normal alkane, dotriacontane (n-C32H66), adsorbed onto a SiO2 surface. Our topographic and frictional images, recorded simultaneously in the contact mode, reveal a multilayer structure in which one to two layers of molecules adsorb adjacent to the SiO2 surface oriented with their long axis parallel to the interface followed by partial layers of molecules oriented perpendicular to the surface. The thicknesses of the parallel and perpendicular layers that we measured with the AFM agree with those inferred from previous x-ray specular reflectivity measurements on similarly prepared samples. We also observe bulk dotriacontane particles and, in contrast with our previous measurements, are able to determine their location. Above a minimum size, the bulk particles are separated from islands of perpendicularly oriented molecules by regions of exposed parallel layers that most likely extend underneath the particles. We find that the lateral friction is sensitive to the molecular orientation in the underlying crystalline film and can be used effectively with topographic measurements to resolve uncertainties in the film structure. We measure the same lateral friction on top of the bulk particles as on the perpendicular layers, a value that is about 2.5 times smaller than on a parallel layer. Scans on top of parallel layers indicate a constant height but reveal domains having different sublevels of friction. We explain this by the domains having different azimuthal orientations of the molecules.

Antithrombotic effect of a new nitric oxide donor (LA419) on experimental thrombogenesis

BACKGROUND

The ability of nitrous compounds to donate nitric oxide (NO), an agent with vasodilating and inhibitory effects on platelet function, has been considered a useful pharmacologic strategy for cardiovascular complications. The purpose of this study was to investigate the effects of a new NO donor, LA419, on platelet interaction in an ex vivo model with human blood circulating through collagen-rich surfaces.

MATERIALS AND METHODS

Platelet adhesive and cohesive function were analyzed by morphometric procedures after perfusion techniques. Treated blood was exposed to thrombogenic surfaces and platelet interactions were morphometrically evaluated.

RESULTS

All the concentrations studied of LA419 (10 microM, 20 microM and 100 microM) reduced overall platelet interaction with a collagen surface (27.19 +/- 4.72; 25.52 +/- 3.52; and 23.44 +/- 3.01, P < 0.05, respectively, vs. 32.31 +/- 1.61% in the control). The antithrombotic effect was confirmed by results in cross-sectional studies performed in arterial vessels exposed to circulating blood. Values of thrombus and covered surface at 20 microM LA419 were, respectively, 13.67 +/- 4.97% and 19.01 +/- 5.89%; respect to controls 34.80 +/- 5.29% and 37.93 +/- 5.34% (P < 0.05). Moreover, LA419 reduced significantly thrombus area (88.45 +/- 21.97 microm(2); P < 0.05) with respect to controls (168.45 +/- 21.97 microm(2)) and thrombus height, from an average of 10.27 +/- 1.05 microm in nontreated blood to 7.16 +/- 0.6 microm in treated samples (P < 0.05).

CONCLUSION

From the present data we can conclude that LA419 possesses a strong antiplatelet action, as demonstrated by its ability to significantly inhibit the interaction of platelet with highly thrombogenic collagen surfaces.

In vitro evaluation of platelet reactivity toward annuloplasty devices treated with heparin coating: Studies under flow conditions

We have applied an in vitro perfusion model to explore the potential thrombogenicity of polyester annulolasty fabric used in valve repair and to investigate the possible thromboresistance characteristics conferred by a special heparin coating (Duraflotrade mark treatment). Samples of human blood from i) untreated or ii) heparin-coated extracorporeal circuits were recirculated through annular perfusion chambers containing a) untreated or b) treated annuloplasty cloth material. Perfusion experiments were performed at a shear rate of 600 s(-1) for 20 min. Platelet interaction with the material was morphometrically evaluated. In experiments performed with blood from untreated circuits and cloth material, the average cross-sectional area of platelet mass was 615 +/- 135 microm2. Treatment of cloth material with Duraflotrade mark statistically decreased the area of interacting platelets to 319 +/- 101 microm2 (*p < 0.05, n = 10). Blood samples from heparin-coated extracorporeal circuits showed a decrease of total area of platelets (308 +/- 58 microm2 vs 138 +/- 30 microm2, *p < 0.05, n = 9). The combined treatment of Duraflotrade mark in extracorporeal circuits and cloth material caused a more consistent reduction (p < 0.05). The in vitro perfusion experimental model was sensitive to evaluate the thrombogenic potential of Duraflotrade mark treatment. Our results indicate that the heparin coating of cloth material and extracorporeal circuits improves the biocompatibility of the original material and reduces the thrombogenic profile.

Critical period for a teratogenic VLA-4 antagonist: Developmental effects and comparison of embryo drug concentrations of teratogenic and non-teratogenic VLA-4 antagonists

BACKGROUND

Integrins such as VLA-4 (Very late antigen 4, integrin alpha4beta1) play key roles in cell-cell interactions that are critical for development. Homozygous null knockouts of the VLA-4 alpha4-subunit or VCAM-1 (VLA-4 cell surface ligand) in mice result in failure of the allantois and chorion to fuse leading to interrupted placentation and cardiac development and embryo lethality. Embryo-fetal studies of three VLA-4 antagonists, IVL745, IVL984, and HMR1031 [Crofts et al., Birth Defects Res B 71:55-68 (this issue), 2004] with exposure on gestation days (GD) 6-17 (rat), 6-18 (rabbit) or 6-15 (mouse) showed that only IVL984 treatment resulted in embryo lethality and cardiac defects. Objectives of the current study were to determine the critical period for inducing IVL984-related embryo-fetal effects, and to test the hypothesis that these effects were due to higher embryo drug concentrations.

METHODS

IVL984 was administered at 40 mg/kg/day to pregnant rats on GD 4 and 5, GD 6 and 7, GD 8 and 9, GD 10 and 11, or GD 12 and 13. Animals were euthanized on GD 21 and uteri and fetuses were examined. A treatment period of GD 10-12 was selected for subsequent toxicokinetic (TK) studies in which IVL984, HMR1031, or IVL745 was administered to pregnant rats and rabbits. On GD 12, maternal plasma, extra-embryonic tissue (placenta and amniotic fluid), and embryonic tissue were collected and analyzed for drug concentrations.

RESULTS

In the IVL984 critical period study in pregnant rats, treatment on GD 10 and 11 resulted in increased post-implantation loss, skeletal variations, and spiral septal defects similar to those observed in standard embryo-fetal development studies with treatment throughout organogenesis. There were no embryo-fetal effects after treatment on GD 4 and 5, GD 6 and 7, or GD 8 and 9. There was a single aorta malformation after treatment on GD 12 and 13. In the TK studies, IVL745, HMR1031, and IVL984 were all detectable in embryonic tissue and there was no evidence for accumulation. Rat and rabbit embryo exposures (AUC or dose-adjusted AUC) on GD 12 could not explain the observed teratology (IVL984<HMR1031<IVL745). Further analyses incorporating pharmacological activity, clearance, and protein binding data provided a positive correlation between embryonic exposure and teratogenic potency.

CONCLUSIONS

The critical period for IVL984 in the rat, GD 10 to 11, corresponds to the expression of alpha-4 integrin on the chorion and VCAM-1 on the allantois and myocardium as well as chorioallantoic fusion and formation of the spiral septum. Embryo drug levels adjusted for pharmacological activity, clearance, and protein binding provide a possible explanation for the differing teratogenic potency of IVL984, HMR1031, and IVL745.

Evaluation of effects of rofecoxib on platelet function in an in vitro model of thrombosis with circulating human blood

BACKGROUND

Cyclooxygenase (COX)-2-selective non-steroidal anti-inflammatory drugs have been used for anti-inflammatory therapy. However, it has also been described that they may increase risk of cardiovascular events.

OBJECTIVES

To study the effects of COX2 inhibitor rofecoxib on platelet function using in vitro tests. Results were compared with those obtained in a parallel experiment with acetyl salicylic acid (ASA).

METHODS

Studies of platelet aggregation, using different agonists, were performed by a turbidimetric method. Adhesive and cohesive function of platelets were analyzed by perfusion techniques, treated blood was exposed to thrombogenic surfaces and platelet interaction was morphometrically evaluated.

RESULTS

Twenty-five micro M of rofecoxib induced a prolonged lag time and a reduction in the percentage of aggregation when arachidonic acid, ADP or collagen were used as agonists. In perfusion studies with parallel chamber rofecoxib 50 microM and ASA 500 microM reduced overall platelet interaction with the collagen surface (17.4 +/- 3.7, P < 0.05; vs. 32.1 +/- 2.6%P < 0.05 and 17.9 +/- 2.4, vs. 31.9 +/- 3.24, P < 0.05, respectively). In studies performed on annular chambers, 25 micro M of rofecoxib reduced platelet interaction; values of the thrombus and covered surface were 17.4 +/- 4.5%; P < 0.05 and 21.1 +/- 4.1%; P < 0.05, respectively, vs. 30.4 +/- 7.5% and 33.5 +/- 6.5 in the control. ASA did also impair thrombus formation but differences did not reach the levels of statistical significance. Moreover, rofecoxib but not ASA reduced significantly thrombus height and thrombus area (7.4 +/- 0.5 microM; P < 0.005 and 96.0 +/- 21.2 microM(2); P < 0.05 vs. control 11.2 +/- 0.9 microM and 220.0 +/- 47.7 microM(2), respectively).

CONCLUSION

We conclude that under our experimental conditions, rofecoxib diminished platelet aggregation induced by different agonists and inhibited platelet-mediated thrombogenesis in an in vitro model of thrombosis.

Different embryo-fetal toxicity effects for three VLA-4 antagonists

BACKGROUND

VLA-4 (Very late antigen 4, integrin alpha4beta1) plays an important role in cell-cell interactions that are critical for development. Homozygous null knockouts of the alpha4 subunit of VLA-4 or VCAM-1 (cell surface ligand to VLA-4) in mice result in abnormal placental and cardiac development and embryo lethality. Objectives of the current study were to assess and compare the teratogenic potential of three VLA-4 antagonists.

METHODS

IVL745, HMR1031, and IVL984 were each evaluated by the subcutaneous route in standard embryo-fetal developmental toxicity studies in rats and rabbits. IVL984 was also evaluated in mice. Fetuses were examined externally, viscerally, and skeletally.

RESULTS

IVL745 did not cause significant maternal or fetal effects at doses up to 100 or 250 mg/kg/day in rats or rabbits, respectively. HMR1031 treatment resulted in marked maternal toxicity and slight fetal toxicity at the highest tested doses of 200 and 75 mg/kg/day in rats and rabbits, respectively. HMR1031 embryo-fetal effects consisted of slightly lower body weight and crown-rump length in rats and minor sternebral defects in rabbits. IVL984 treatment resulted in minimal maternal effects at doses up to 40, 15, and 100 mg/kg/day in rats, rabbits, and mice, respectively (excluding abortions in rabbits). However, marked developmental effects were observed at the lowest tested IVL984 doses, 1, 0.2, and 3 mg/kg/day in rats, rabbits, and mice, respectively. IVL984 embryo-fetal effects consisted of increased total post-implantation loss due to early resorptions and high incidences of cardiac malformations and skeletal malformations and/or variations. Notably, spiral septal defects were observed in up to 76% of rat fetuses and up to 58% of rabbit fetuses.

CONCLUSIONS

Dramatic differences in teratogenic potential were observed: IVL745 was not teratogenic, HMR1031 caused slight embryo-fetal effects at maternally-toxic doses, and IVL984 was a potent teratogen at doses where direct maternal toxicity was limited to abortions in rabbits. Prominent effects of IVL984 included embryo lethality and cardiac malformations including spiral septal defects in three species.

Concentrates containing factor IX could improve haemostasis under conditions of thrombocytopenia: studies in an in vitro model

BACKGROUND AND OBJECTIVES

We explored the effect on haemostasis of different factor IX (FIX) concentrates under thrombocytopenic conditions using an in vitro perfusion technique.

MATERIALS AND METHODS

A moderate experimental thrombocytopenia (25 000-30 000 platelets/microl) was induced by means of a filtration procedure in blood anticoagulated with low-molecular-weight heparin. The effects of three different FIX concentrates - a prothrombin complex concentrate (PCC), an intermediate-purity concentrate (FIX/X), and a high-purity concentrate (HPFIX) - on platelet deposition and fibrin formation on subendothelium were assessed at two different shear rates (600/second and 1200/second). Activation of the coagulation system was monitored through assessment of prothrombin activation fragment 1 + 2 (F1 + 2).

RESULTS

Fibrin deposition increased after addition of FIX concentrates, but only showed a significant increase in experiments performed after incubation of PCC at the lower shear rate (600/second) (64.25 +/- 9.61% vs. control 31.22 +/- 8.02%; P < 0.05). Addition of FIX concentrates caused a small increase in the percentage of platelet deposition and area of those aggregates. These differences reached levels of statistical significance in the presence of FIX/X and HPFIX in experiments performed at a shear rate of 600/second. F1 + 2 baseline values in anticoagulated thrombocytopenic blood were 1.15 +/- 0.13 nm and reached levels of 2.49 +/- 0.24 and 3.60 +/- 0.33 nm at shear rates of 600 and 1200/second, respectively. Increments in F1 + 2 observed after addition of different FIX concentrates always remained in the previous ranges.

CONCLUSIONS

Data from the present study provide experimental support favouring the concept that FIX concentrates containing other activated factors could improve haemostasis under conditions of moderate thrombocytopenia.

[Merkel cell carcinoma]

The authors present 2 cases of Merkel cell carcinoma in the head and neck district, evaluating the characteristics and evolution. Merkel cell carcinoma is a rare, highly aggressive neuroendocrine cutaneous neoplasm which is often located in the head and neck district. This carcinoma has the same characteristics as small cell tumors and tends to significant metastatization both through the lymph nodes and through the blood. It is also prone to frequent recurrence. Today diagnosis is facilitated by electron microscopy and immunohistochemistry to search for neurofilaments and cytocheratin 20. The treatment of choice is radical surgery ensuring a tumor-free edge of at least 3 cm, associated with supplementary local radiotherapy. Recurrence is quite frequent despite the treatment strategies applied.

Infusible platelet membranes improve hemostasis in thrombocytopenic blood: experimental studies under flow conditions

BACKGROUND

The potential hemostatic effect of infusible platelet membranes (IPM; Cyplex, Cypress Bioscience) prepared from outdated human platelets is investigated.

STUDY DESIGN AND METHODS

Increasing concentrations of IPM were added to blood samples anticoagulated with low-molecular-weight heparin, in which platelets and WBC counts had been experimentally reduced by a filtration procedure. Thrombocytopenic blood with IPM was circulated in a perfusion chamber at various shear rates (300, 600, and 1200/sec(-1)), and platelet and fibrin deposition on the surface of a damaged vessel was measured. Prothrombin fragments 1 and 2 (F1+2) levels were also monitored.

RESULTS

Under conditions of severe thrombocytopenia (<6000 platelets/microL) IPM did not increase platelet deposition. However, a dose-dependent increase in fibrin deposition was observed with concentrations of IPM ranging from 0.5 to 2 mg per kg in perfusions at 300 and 600 per sec(-1) (p<0.05 vs. thrombocytopenic blood). Experimental studies performed under conditions of moderate thrombocytopenia and higher shear rates (25, 000-30,000 platelets/microL; at 600 and 1200/sec(-1)) showed that IPM concentrations equivalent to 0.5 or 1 mg per kg improved fibrin deposition (33.5 +/- 9.5% and 37.7 +/- 12.8%, respectively, vs. 22.7 +/- 5.2% in controls) and also promoted a moderate increase in platelet deposition, with a concomitant significant increase in the size of platelet aggregates (p<0.05). Exposure of thrombocytopenic blood to a damaged vessel resulted in an increase of F1+2 levels from 0.8 +/- 0.15 to 1.7 +/- 0.22 nM at 300 per sec(-1) and 1.94 +/- 0.46 nM at 600 per sec(-1). Postperfusion levels of F1+2 after the addition of IPM were always similar to levels in untreated controls.

CONCLUSION

IPM promotes local procoagulant activity at sites of vascular damage under conditions of severe and moderate thrombocytopenia. IPM also appears to facilitate platelet cohesive functions under conditions of moderate thrombocytopenia.

Benign symmetric lipomatosis (Madelung's disease)

We report on a 50-year-old man who presented with benign, symmetric lipomatosis and chronic alcoholic liver disease. The characteristic clinical features and a brief review of the current literature are presented.

Evaluation of acquired platelet dysfunctions in uremic and cirrhotic patients using the platelet function analyzer (PFA-100 ): influence of hematocrit elevation

BACKGROUND AND OBJECTIVE

Patients with end-stage renal disease or advanced cirrhosis develop bleeding disorders characterized by defective interaction of platelets with damaged subendothelium. The anemia associated with both clinical entities has a negative influence on hemostasis. We evaluated alterations of platelet function in patients suffering from end-stage renal disease (n=21) or hepatic cirrhosis (n=20) using standard aggregometric techniques and the recently developed platelet function analyzer (PFA-100 ). The impact of low hematocrit was also analyzed.

DESIGN AND METHODS

The hemostatic capacity of platelets was tested in the PFA-100 using citrated blood and standard cartridges containing collagen-ADP (COL-ADP) or collagen-epinephrine (COL-Epi). The hemodynamic influence of hematocrit was also evaluated in blood aliquots in which hematocrit was experimentally increased by adding red blood cells from the same patient.

RESULTS

Aggregation studies demonstrated abnormal responses to several agonists in both group of patients. Closure times obtained by the PFA-100 for control blood samples were 87+/-3 sec for COL-ADP and 113+/-5 sec with COL-EPi cartridges. Closure times in uremic and cirrhotic patients with average hematocrits of 0.26 and 0.27 respectively were significantly prolonged (139+/-12 and 125+/-14 sec, respectively with COL-ADP and 194+/-29 and 151+/-15 sec with COL-Epi cartridges). A 5% increase in the hematocrit caused a reduction in the closure time to 111+/-7 sec (COL-ADP) and 143+/-14 sec (COL-Epi) in the uremic group and to 86+/-4 sec (COL-ADP) and 115+/-16 sec (COL-Epi) in the cirrhotic group. Our studies confirm the platelet dysfunction in uremic and cirrhotic patients.

INTERPRETATION AND CONCLUSIONS

The PFA-100 device proved to be useful for testing alterations of primary hemostasis in these acquired disorders and was sensitive enough to detect modifications in hemostasis caused by elevations in hematocrit. Conventional aggregometric tests were able to identify the intrinsic platelet abnormality in uremic and cirrhotic conditions, while the PFA-100 seemed more sensitive in detecting the negative influence of the hematocrit reduction.

[Functionality of von Willebrand factor present in Fanhdi: adhesion to the vascular subendothelium in vitro]

PURPOSE

To study the ability of VWF present in a plasma derived high purity factor VIII concentrate (> or = 100 UI FVIII/mg of protein, Fanhdi) to promote deposition and platelet adhesion on the injured vessel wall, as an indicator of the functionality of said VWF.

MATERIAL AND METHODS

An in vitro perfusion system was employed. Adequate proportions of platelets and red cells were suspended in a human albumin solution. Aliquots of the studied product were added to obtain levels of 0.4 and 0.8 VWF:AG U/mL in the perfusates. As a comparative group, cryoprecipitate was assayed at similar VWF:Ag doses. Perfusions were performed on rabbit de-endothelialized abdominal aorta segments, placed in annular perfusion chambers, at 37 degrees C and at a flux of 140 mL/min (800 s-1) for 10 min. Results were evaluated as surface covered by platelets and as the percentage ratio between thrombus and surface covered by platelets. FVIII activity was determined by one stage clotting assay. VWF:RCo activity was determined by aggregometry and VWF:Ag by ELISA.

RESULTS

The VWF:Ag/FVIII:C ratio of Fanhdi is 1.57, while VWF:Roc/FVIII:C ratio is 1.15. The values of platelet deposition obtained, expressed as times of increase in the surface covered by platelets, considering the basal value (without VWF added) as 1, were: Cryoprecipitate 0.4 = 1.93; Cryoprecipitate 0.8 = 2.21; Fanhdi 0.4 = 2.99; Fanhdi 0.8 = 3.40. The ratios between thrombus and surface covered are 13.23%, 23.84%, 42.23%, 21.93% and 26.25% respectively.

CONCLUSIONS

These data show that VWF present in Fanhdi maintains a high degree of functionality, promoting platelet adhesion on subendothelium under flow conditions, after its incorporation into an albumin-platelet-red cell preparation and resulting in a significant increase in platelet adhesion when compared to the VWF-free basal control.